diff --git a/src/CHANGELOG b/src/CHANGELOG
index e14edb7d7..211306ad7 100644
--- a/src/CHANGELOG
+++ b/src/CHANGELOG
@@ -1016,8 +1016,8 @@ ECL 0.7
     RECURSIVE-P is NIL. Furthermore, EOF is detected when EOF-ERROR-P
     is true, regardless of the value of RECURSIVE-P.
 
-ECL 0.7b
-========
+ECL 0.8
+=======
 
 * Errors fixed:
 
@@ -1112,6 +1112,19 @@ ECL 0.7b
 
   - cl_special_form_p() renamed to cl_special_operator_p().
 
+  - If a wrong number of arguments is passed to a function, the name of
+    the function is mentioned in the error message, whenever possible.
+
+  - The tests for the type and size of cl_fixnum have been
+    grouped. FIXNUM_BITS and CHAR_BIT do not rely now on "char" being
+    8-bit large.
+
+  - All configuration settings are now grouped in config.h. This file
+    has two parts, and the second one, containing flags which are only
+    needed during the build process, is deleted when installing ECL.
+
+  - File critical.h merged into lwp.h.
+
 * ANSI compatibility:
 
   - DEFINE-SYMBOL-MACRO finally implemented.
@@ -1120,6 +1133,13 @@ ECL 0.7b
 
   - Added function ENSURE-DIRECTORIES-EXIST.
 
+  - CODE-CHAR would reject negative numbers.
+
+  - Remove si::*inhibit-macro-special*. When a special operator is
+    redefined as a macro, preserve the special nature of the
+    operator. Complain when user tries to redefine a special operator
+    as a function.
+
 TODO:
 =====
 
diff --git a/src/aclocal.m4 b/src/aclocal.m4
index 1d8f9f727..2b40d3831 100644
--- a/src/aclocal.m4
+++ b/src/aclocal.m4
@@ -99,6 +99,9 @@ configure___LDFLAGS=LDFLAGS
 configure___SHARED_LDFLAGS=SHARED_LDFLAGS
 #endif
 
+configure___ecl_setjmp=ecl_setjmp
+configure___ecl_longjmp=ecl_longjmp
+
 configure___architecture=ARCHITECTURE
 configure___software_type=SOFTWARE_TYPE
 configure___software_version=SOFTWARE_VERSION
@@ -127,6 +130,10 @@ AC_MSG_CHECKING(for software type)
 AC_MSG_RESULT([${software_type}])
 AC_MSG_CHECKING(for software version)
 AC_MSG_RESULT([${software_version}])
+AC_MSG_CHECKING(use setjmp or _setjmp)
+AC_MSG_RESULT([${ecl_setjmp}])
+AC_MSG_CHECKING(use longjmp or _longjmp)
+AC_MSG_RESULT([${ecl_longjmp}])
 ])
 dnl
 dnl --------------------------------------------------------------
@@ -196,46 +203,37 @@ dnl enough that convertion back and forth to pointer implies no
 dnl loss of information.
 AC_DEFUN(ECL_FIXNUM_TYPE,[
 AC_MSG_CHECKING(appropiate type for fixnums)
-dnl
-dnl 1.- Guess the type of a fixnum
-dnl
 AC_TRY_RUN([#include <stdio.h>
 int main() {
+  const char *int_type;
+  int bits;
   FILE *f=fopen("conftestval", "w");
   if (!f) exit(1);
   if (sizeof(int) >= sizeof(void*)) {
-    fprintf(f, "int\n");
+    unsigned int t = 1, l;
+    int_type="int";
+    for (bits=0; ((t << 1) >> 1) == t; bits++, t <<= 1);
+    l = (~0) << (bits - 2);
+    fprintf(f,"CL_FIXNUM_MIN='%d';",l);
+    fprintf(f,"CL_FIXNUM_MAX='%d';",-(l+1));
   } else if (sizeof(long) >= sizeof(void*)) {
-    fprintf(f, "long\n");
+    unsigned long int t = 1, l;
+    int_type="long int";
+    for (bits=0; ((t << 1) >> 1) == t; bits++, t <<= 1);
+    l = (~0) << (bits - 2);
+    fprintf(f,"CL_FIXNUM_MIN='%ld';",l);
+    fprintf(f,"CL_FIXNUM_MAX='%ld';",-(l+1));
   } else
     exit(1);
+  fprintf(f,"CL_FIXNUM_TYPE='%s';",int_type);
+  fprintf(f,"CL_FIXNUM_BITS='%d'",bits);
   exit(0);
 }],
-cl_fixnum=`cat conftestval`
-AC_MSG_RESULT([${cl_fixnum}])
-AC_DEFINE_UNQUOTED(CL_FIXNUM_TYPE,${cl_fixnum}),
-AC_MSG_ERROR(There is no appropiate integer type for the cl_fixnum type))
-dnl
-dnl 2.- Guess the size of a fixnum
-dnl
-AC_MSG_CHECKING(most positive fixnum)
-AC_TRY_RUN([#include <stdio.h>
-int main() {
-  ${cl_fixnum} i=0,j,k;
-  FILE *f=fopen("conftestval", "w");
-  if (!f) exit(1);
-  do {
-    k = i * 2 + 1;
-    if (k == i) exit(1);
-    i = k;
-    j = (i << 2) >> 2;
-    fprintf(stderr,"%d\n",i);
-  } while (i == j);
-  fprintf(f, "0x%xL\n", (long)i >> 1);
-  exit(0);
-}],
-cl_fixnum_limit=`cat conftestval`
-AC_MSG_RESULT([${cl_fixnum_limit}])
-AC_DEFINE_UNQUOTED(MOST_POSITIVE_FIXNUM, ${cl_fixnum_limit}),
+eval "`cat conftestval`"
+AC_MSG_RESULT([${CL_FIXNUM_TYPE}])
+AC_SUBST(CL_FIXNUM_TYPE)
+AC_SUBST(CL_FIXNUM_BITS)
+AC_SUBST(CL_FIXNUM_MAX)
+AC_SUBST(CL_FIXNUM_MIN),
 AC_MSG_ERROR(There is no appropiate integer type for the cl_fixnum type))
 ])
diff --git a/src/c/Makefile.in b/src/c/Makefile.in
index 5591752cc..7313a5876 100644
--- a/src/c/Makefile.in
+++ b/src/c/Makefile.in
@@ -30,7 +30,7 @@ HFILES	= ../h/config.h $(HDIR)/ecl.h $(HDIR)/ecl-cmp.h\
 	$(HDIR)/machines.h $(HDIR)/object.h $(HDIR)/cs.h $(HDIR)/stacks.h\
 	$(HDIR)/external.h $(HDIR)/eval.h\
 	$(HDIR)/number.h $(HDIR)/page.h $(HDIR)/unify.h\
-	$(HDIR)/lwp.h $(HDIR)/critical.h
+	$(HDIR)/lwp.h
 OBJS	= main.o symbol.o package.o list.o\
 	apply.o eval.o interpreter.o compiler.o disassembler.o \
 	clos.o instance.o gfun.o reference.o character.o\
@@ -57,6 +57,8 @@ all:	$(DPP) ../libecl.a cinit.o
 
 install: $(HFILES)
 	$(INSTALL_DATA) $(HFILES) $(PREFIX)$(libdir)/h/
+	sed ',-CUT-,$$d' ../h/config.h > ../h/config-install.h
+	$(INSTALL_DATA) ../h/config-install.h $(PREFIX)$(libdir)/h/config.h
 
 ../libecl.a: $(OBJS)
 	ar cr $@ $(OBJS)
diff --git a/src/c/array.d b/src/c/array.d
index be9350a38..1daa5c6bd 100644
--- a/src/c/array.d
+++ b/src/c/array.d
@@ -14,12 +14,9 @@
     See file '../Copyright' for full details.
 */
 
+#include <limits.h>
 #include "ecl.h"
 
-#ifndef CHAR_BIT
-#define CHAR_BIT (sizeof(char)*8)
-#endif
-
 static void displace (cl_object from, cl_object to, cl_object offset);
 static void check_displaced (cl_object dlist, cl_object orig, cl_index newdim);
 extern cl_elttype get_elttype (cl_object x);
diff --git a/src/c/cmpaux.d b/src/c/cmpaux.d
index 7d47f1796..f67a41b8b 100644
--- a/src/c/cmpaux.d
+++ b/src/c/cmpaux.d
@@ -14,13 +14,10 @@
     See file '../Copyright' for full details.
 */
 
+#include <limits.h>
 #include "ecl.h"
 #include "ecl-inl.h"
 
-#ifndef CHAR_BIT
-#define CHAR_BIT (sizeof(char)*8)
-#endif
-
 cl_object
 si_specialp(cl_object sym)
 {
diff --git a/src/c/file.d b/src/c/file.d
index 04663ed73..361622cfc 100644
--- a/src/c/file.d
+++ b/src/c/file.d
@@ -22,6 +22,7 @@
 */
 
 #include <ecl.h>
+#include "machines.h"
 
 #if defined(BSD) && !defined(MSDOS)
 #include <sys/ioctl.h>
diff --git a/src/c/load.d b/src/c/load.d
index facb4dca4..80d740175 100644
--- a/src/c/load.d
+++ b/src/c/load.d
@@ -14,6 +14,7 @@
 */
 
 #include "ecl.h"
+#include "machines.h"
 #include "ecl-inl.h"
 
 #ifdef __mips
diff --git a/src/c/main.d b/src/c/main.d
index 41e17ebbb..7a1889c61 100644
--- a/src/c/main.d
+++ b/src/c/main.d
@@ -35,6 +35,7 @@ int data_start = (int)&data_start;
 
 #include <stdlib.h>
 #include "ecl.h"
+#include "machines.h"
 #ifdef TK
 # include "tk.h"
 #endif
diff --git a/src/c/read.d b/src/c/read.d
index 55b279d4f..176ca5926 100644
--- a/src/c/read.d
+++ b/src/c/read.d
@@ -14,15 +14,13 @@
     See file '../Copyright' for full details.
 */
 
+#include <limits.h>
 #include <math.h>
 #include <ctype.h>
 #include "ecl.h"
+#include "internal.h"
 #include "ecl-inl.h"
 
-#ifndef CHAR_BIT
-#define CHAR_BIT (sizeof(char)*8)
-#endif
-
 /******************************* EXPORTS ******************************/
 
 cl_object standard_readtable;
diff --git a/src/c/sequence.d b/src/c/sequence.d
index 37cdf1aea..1b1267c63 100644
--- a/src/c/sequence.d
+++ b/src/c/sequence.d
@@ -14,13 +14,10 @@
     See file '../Copyright' for full details.
 */
 
+#include <limits.h>
 #include "ecl.h"
 #include "ecl-inl.h"
 
-#ifndef CHAR_BIT
-#define CHAR_BIT (sizeof(char)*8)
-#endif
-
 #undef endp
 
 #define	endp(obje)	(endp_temp = (obje), CONSP(endp_temp) ? \
diff --git a/src/c/unixfsys.d b/src/c/unixfsys.d
index a7eb5a790..221a556a7 100644
--- a/src/c/unixfsys.d
+++ b/src/c/unixfsys.d
@@ -20,8 +20,9 @@
 #include <sys/types.h>
 #include <pwd.h>
 #include <sys/stat.h>
-#include "ecl.h"
 #include <stdlib.h>
+#include "ecl.h"
+#include "machines.h"
 #ifdef BSD
 #include <dirent.h>
 #else
diff --git a/src/c/unixsys.d b/src/c/unixsys.d
index 6ab04d8ca..e54e9a686 100644
--- a/src/c/unixsys.d
+++ b/src/c/unixsys.d
@@ -14,76 +14,9 @@
     See file '../Copyright' for full details.
 */
 
+#include <stdlib.h>
 #include "ecl.h"
-#include <stdlib.h>
-
-#if 0
-#if !defined(__stdlib_h) && !defined(_STDLIB_H_) && !defined(__STDLIB_H__) &&  !defined(_STDLIB_H)
-#include <signal.h>
-int
-system(const char *command)
-{
-	char buf[4];
-	extern sigint();
-
-	signal(SIGINT, SIG_IGN);
-	write(4, command, strlen(command)+1);
-	read(5, buf, 1);
-	signal(SIGINT, sigint);
-	return(buf[0]<<8);
-}
-#endif /* __STDLIB_H__ */
-
-#if defined(__FreeBSD__) || defined(__NetBSD__)
-
-/* due to the calls to realloc in system.c/exec.c (memory which hasn't been
-malloc'ed can't be realloced in ecl) we have to patch this a bit.
-We use execv and supply the arg list, so execl doesn't have to realloc. CvdL */
-
-#include <sys/types.h>
-#include <sys/signal.h>
-#include <sys/wait.h>
-#include <signal.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <unistd.h>
-#include <paths.h>
-
-int
-system(const char *command)
-{
-	union wait pstat;
-	pid_t pid;
-	int omask;
-	sig_t intsave, quitsave;
-
-	if (!command)		/* just checking... */
-		return(1);
-
-	omask = sigblock(sigmask(SIGCHLD));
-	switch(pid = vfork()) {
-	case -1:			/* error */
-		(void)sigsetmask(omask);
-		pstat.w_status = 0;
-		pstat.w_retcode = 127;
-		return(pstat.w_status);
-	case 0:	{			/* child */
-		char *args[] = { "sh", "-c", command, (char *)NULL };
-		(void)sigsetmask(omask);
-	        execv(_PATH_BSHELL, args);
-		_exit(127);
-	}
-	}
-	intsave = signal(SIGINT, SIG_IGN);
-	quitsave = signal(SIGQUIT, SIG_IGN);
-	pid = waitpid(pid, (int *)&pstat, 0);
-	(void)sigsetmask(omask);
-	(void)signal(SIGINT, intsave);
-	(void)signal(SIGQUIT, quitsave);
-	return(pid == -1 ? -1 : pstat.w_status);
-}
-#endif
-#endif
+#include "machines.h"
 
 cl_object
 si_system(cl_object cmd)
diff --git a/src/configure b/src/configure
index a9b4439af..cdead9a12 100755
--- a/src/configure
+++ b/src/configure
@@ -1312,8 +1312,6 @@ test -z "$host_alias" &&
   host_alias=$ac_cv_host
 
 
-ac_config_headers="$ac_config_headers h/config.h"
-
 
 
 
@@ -3796,6 +3794,9 @@ configure___LDFLAGS=LDFLAGS
 configure___SHARED_LDFLAGS=SHARED_LDFLAGS
 #endif
 
+configure___ecl_setjmp=ecl_setjmp
+configure___ecl_longjmp=ecl_longjmp
+
 configure___architecture=ARCHITECTURE
 configure___software_type=SOFTWARE_TYPE
 configure___software_version=SOFTWARE_VERSION
@@ -3835,6 +3836,14 @@ echo "$as_me:$LINENO: checking for software version" >&5
 echo $ECHO_N "checking for software version... $ECHO_C" >&6
 echo "$as_me:$LINENO: result: ${software_version}" >&5
 echo "${ECHO_T}${software_version}" >&6
+echo "$as_me:$LINENO: checking use setjmp or _setjmp" >&5
+echo $ECHO_N "checking use setjmp or _setjmp... $ECHO_C" >&6
+echo "$as_me:$LINENO: result: ${ecl_setjmp}" >&5
+echo "${ECHO_T}${ecl_setjmp}" >&6
+echo "$as_me:$LINENO: checking use longjmp or _longjmp" >&5
+echo $ECHO_N "checking use longjmp or _longjmp... $ECHO_C" >&6
+echo "$as_me:$LINENO: result: ${ecl_longjmp}" >&5
+echo "${ECHO_T}${ecl_longjmp}" >&6
 
 
 if test "x$prefix" = "xNONE"; then prefix=${ac_default_prefix}; fi
@@ -4086,14 +4095,28 @@ else
 #include "confdefs.h"
 #include <stdio.h>
 int main() {
+  const char *int_type;
+  int bits;
   FILE *f=fopen("conftestval", "w");
   if (!f) exit(1);
   if (sizeof(int) >= sizeof(void*)) {
-    fprintf(f, "int\n");
+    unsigned int t = 1, l;
+    int_type="int";
+    for (bits=0; ((t << 1) >> 1) == t; bits++, t <<= 1);
+    l = (~0) << (bits - 2);
+    fprintf(f,"CL_FIXNUM_MIN='%d';",l);
+    fprintf(f,"CL_FIXNUM_MAX='%d';",-(l+1));
   } else if (sizeof(long) >= sizeof(void*)) {
-    fprintf(f, "long\n");
+    unsigned long int t = 1, l;
+    int_type="long int";
+    for (bits=0; ((t << 1) >> 1) == t; bits++, t <<= 1);
+    l = (~0) << (bits - 2);
+    fprintf(f,"CL_FIXNUM_MIN='%ld';",l);
+    fprintf(f,"CL_FIXNUM_MAX='%ld';",-(l+1));
   } else
     exit(1);
+  fprintf(f,"CL_FIXNUM_TYPE='%s';",int_type);
+  fprintf(f,"CL_FIXNUM_BITS='%d'",bits);
   exit(0);
 }
 _ACEOF
@@ -4108,67 +4131,12 @@ if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
   ac_status=$?
   echo "$as_me:$LINENO: \$? = $ac_status" >&5
   (exit $ac_status); }; }; then
-  cl_fixnum=`cat conftestval`
-echo "$as_me:$LINENO: result: ${cl_fixnum}" >&5
-echo "${ECHO_T}${cl_fixnum}" >&6
-cat >>confdefs.h <<_ACEOF
-#define CL_FIXNUM_TYPE ${cl_fixnum}
-_ACEOF
+  eval "`cat conftestval`"
+echo "$as_me:$LINENO: result: ${CL_FIXNUM_TYPE}" >&5
+echo "${ECHO_T}${CL_FIXNUM_TYPE}" >&6
+
+
 
-else
-  echo "$as_me: program exited with status $ac_status" >&5
-echo "$as_me: failed program was:" >&5
-cat conftest.$ac_ext >&5
-( exit $ac_status )
-{ { echo "$as_me:$LINENO: error: There is no appropiate integer type for the cl_fixnum type" >&5
-echo "$as_me: error: There is no appropiate integer type for the cl_fixnum type" >&2;}
-   { (exit 1); exit 1; }; }
-fi
-rm -f core core.* *.core conftest$ac_exeext conftest.$ac_objext conftest.$ac_ext
-fi
-echo "$as_me:$LINENO: checking most positive fixnum" >&5
-echo $ECHO_N "checking most positive fixnum... $ECHO_C" >&6
-if test "$cross_compiling" = yes; then
-  { { echo "$as_me:$LINENO: error: cannot run test program while cross compiling" >&5
-echo "$as_me: error: cannot run test program while cross compiling" >&2;}
-   { (exit 1); exit 1; }; }
-else
-  cat >conftest.$ac_ext <<_ACEOF
-#line $LINENO "configure"
-#include "confdefs.h"
-#include <stdio.h>
-int main() {
-  ${cl_fixnum} i=0,j,k;
-  FILE *f=fopen("conftestval", "w");
-  if (!f) exit(1);
-  do {
-    k = i * 2 + 1;
-    if (k == i) exit(1);
-    i = k;
-    j = (i << 2) >> 2;
-    fprintf(stderr,"%d\n",i);
-  } while (i == j);
-  fprintf(f, "0x%xL\n", (long)i >> 1);
-  exit(0);
-}
-_ACEOF
-rm -f conftest$ac_exeext
-if { (eval echo "$as_me:$LINENO: \"$ac_link\"") >&5
-  (eval $ac_link) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); } && { ac_try='./conftest$ac_exeext'
-  { (eval echo "$as_me:$LINENO: \"$ac_try\"") >&5
-  (eval $ac_try) 2>&5
-  ac_status=$?
-  echo "$as_me:$LINENO: \$? = $ac_status" >&5
-  (exit $ac_status); }; }; then
-  cl_fixnum_limit=`cat conftestval`
-echo "$as_me:$LINENO: result: ${cl_fixnum_limit}" >&5
-echo "${ECHO_T}${cl_fixnum_limit}" >&6
-cat >>confdefs.h <<_ACEOF
-#define MOST_POSITIVE_FIXNUM ${cl_fixnum_limit}
-_ACEOF
 
 else
   echo "$as_me: program exited with status $ac_status" >&5
@@ -5614,6 +5582,10 @@ ac_config_files="$ac_config_files compile.lsp compile_rest.lsp bare.lsp lsp/conf
 
 ac_config_files="$ac_config_files ecl-config:util/ecl-config"
 
+ac_config_files="$ac_config_files h/configpre:h/config.h.in"
+
+ac_config_headers="$ac_config_headers h/config.h:h/configpre"
+
 cat >confcache <<\_ACEOF
 # This file is a shell script that caches the results of configure
 # tests run on this system so they can be shared between configure
@@ -6106,7 +6078,8 @@ do
   "cmp/defsys.lsp" ) CONFIG_FILES="$CONFIG_FILES cmp/defsys.lsp" ;;
   "clos/defsys.lsp" ) CONFIG_FILES="$CONFIG_FILES clos/defsys.lsp" ;;
   "ecl-config" ) CONFIG_FILES="$CONFIG_FILES ecl-config:util/ecl-config" ;;
-  "h/config.h" ) CONFIG_HEADERS="$CONFIG_HEADERS h/config.h" ;;
+  "h/configpre" ) CONFIG_FILES="$CONFIG_FILES h/configpre:h/config.h.in" ;;
+  "h/config.h" ) CONFIG_HEADERS="$CONFIG_HEADERS h/config.h:h/configpre" ;;
   *) { { echo "$as_me:$LINENO: error: invalid argument: $ac_config_target" >&5
 echo "$as_me: error: invalid argument: $ac_config_target" >&2;}
    { (exit 1); exit 1; }; };;
@@ -6223,6 +6196,8 @@ s,@SHARED_LDFLAGS@,$SHARED_LDFLAGS,;t t
 s,@architecture@,$architecture,;t t
 s,@software_type@,$software_type,;t t
 s,@software_version@,$software_version,;t t
+s,@ecl_setjmp@,$ecl_setjmp,;t t
+s,@ecl_longjmp@,$ecl_longjmp,;t t
 s,@SHORT_SITE_NAME@,$SHORT_SITE_NAME,;t t
 s,@LONG_SITE_NAME@,$LONG_SITE_NAME,;t t
 s,@EXTRA_OBJS@,$EXTRA_OBJS,;t t
@@ -6241,6 +6216,10 @@ s,@MACHINE_VERSION@,$MACHINE_VERSION,;t t
 s,@OS_TYPE@,$OS_TYPE,;t t
 s,@OS_RELEASE@,$OS_RELEASE,;t t
 s,@DOWN_STACK@,$DOWN_STACK,;t t
+s,@CL_FIXNUM_TYPE@,$CL_FIXNUM_TYPE,;t t
+s,@CL_FIXNUM_BITS@,$CL_FIXNUM_BITS,;t t
+s,@CL_FIXNUM_MAX@,$CL_FIXNUM_MAX,;t t
+s,@CL_FIXNUM_MIN@,$CL_FIXNUM_MIN,;t t
 s,@X_CFLAGS@,$X_CFLAGS,;t t
 s,@X_PRE_LIBS@,$X_PRE_LIBS,;t t
 s,@X_LIBS@,$X_LIBS,;t t
diff --git a/src/configure.in b/src/configure.in
index 4c65f2c3c..99abb6956 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -37,7 +37,6 @@ AC_SUBST(ECL_VERSION)
 dnl Guess operating system of host. We do not allow cross-compiling.
 AC_CANONICAL_HOST
 
-AC_CONFIG_HEADER(h/config.h)
 AC_SUBST(host)
 AC_SUBST(bindir)
 AC_SUBST(mandir)
@@ -109,6 +108,8 @@ AC_SUBST(SHARED_LDFLAGS)dnl	Flags for shared libraries linker
 AC_SUBST(architecture)dnl	Type of processor for which this is compiled
 AC_SUBST(software_type)dnl	Type of operating system
 AC_SUBST(software_version)dnl	Version number of operating system
+AC_SUBST(ecl_setjmp)dnl		Function to use for setjmp
+AC_SUBST(ecl_longjmp)dnl	Function to use for longjmp
 AC_SUBST(SHORT_SITE_NAME)dnl	Short name for the machine we built this on
 AC_SUBST(LONG_SITE_NAME)dnl	Long name for the machine we built this on
 AC_SUBST(EXTRA_OBJS)dnl		Extra *.o files to be compiled into libecl.a
@@ -321,10 +322,15 @@ fi
 dnl ---------------------------------------------------------------------
 dnl		Final pass over configuration files
 dnl
+dnl Notice that we build ${builddir}/h/configpre.h fron ${srcdir}/h/config.h.in,
+dnl and then use all AC_DEF* to build h/config.h from h/configpre.h
+dnl
 AC_CONFIG_FILES(compile.lsp compile_rest.lsp bare.lsp
  lsp/config.lsp cmp/cmpcfg.lsp lsp/load.lsp clos/load.lsp cmp/load.lsp
  ../Makefile Makefile c/Makefile doc/Makefile
  tk/Makefile clx/defsys.lsp tests/Makefile ansi-tests/Makefile gabriel/Makefile
  lsp/defsys.lsp cmp/defsys.lsp clos/defsys.lsp)
 AC_CONFIG_FILES([ecl-config:util/ecl-config],[chmod +x ecl-config])
+AC_CONFIG_FILES([h/configpre:h/config.h.in])
+AC_CONFIG_HEADER([h/config.h:h/configpre])
 AC_OUTPUT
diff --git a/src/h/config.h.in b/src/h/config.h.in
index 7fbab369b..8d1f2a274 100644
--- a/src/h/config.h.in
+++ b/src/h/config.h.in
@@ -3,6 +3,7 @@
 */
 /*
     Copyright (c) 1990, Giuseppe Attardi.
+    Copyright (c) 2001, Juan Jose Garcia Ripoll.
 
     ECoLisp is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
@@ -12,17 +13,77 @@
     See file '../Copyright' for full details.
 */
 
+/*
+ * FEATURES LINKED IN
+ */
+/* Always use CLOS							*/
+#define CLOS
 
-/* -------------------------------------------------------------------- *
- *	OPTIONS								*
- * -------------------------------------------------------------------- */
+/* Use Boehm's garbage collector					*/
+#undef GBC_BOEHM
 
-#define CLOS			/* Always use CLOS			*/
+/* Userland threads?							*/
 #undef THREADS
-#undef TK
 
 /* Network streams							*/
 #undef TCP
+
+/*
+ * C TYPES AND SYSTEM LIMITS
+ */
+/*
+ * The integer type
+ *
+ * cl_fixnum must be an integer type, large enough to hold a pointer.
+ * Ideally, according to the ISOC99 standard, we should use intptr_t,
+ * but the required headers are not present in all systems. Hence we
+ * use autoconf to guess the following values.
+ */
+#define FIXNUM_BITS		@CL_FIXNUM_BITS@
+#define MOST_POSITIVE_FIXNUM	((cl_fixnum)@CL_FIXNUM_MAX@)
+#define MOST_NEGATIVE_FIXNUM	((cl_fixnum)@CL_FIXNUM_MIN@)
+
+typedef @CL_FIXNUM_TYPE@ cl_fixnum;
+typedef unsigned @CL_FIXNUM_TYPE@ cl_index;
+typedef unsigned @CL_FIXNUM_TYPE@ cl_hashkey;
+
+/*
+ * The character type
+ */
+#define	CHAR_CODE_LIMIT		256
+
+/*
+ * Array limits
+ */
+#define	ARANKLIM	64		/*  array rank limit  		*/
+#define	ADIMLIM		16*1024*1024	/*  array dimension limit	*/
+#define	ATOTLIM		16*1024*1024	/*  array total limit		*/
+
+/*
+ * Function limits
+ */
+/*	Maximum number of function arguments 				*/
+#define CALL_ARGUMENTS_LIMIT @CL_FIXNUM_MAX@
+
+/*	Maximum number of required arguments				*/
+#define LAMBDA_PARAMETERS_LIMIT 64
+
+/*	Numb. of args. which can be passed using the C stack		*/
+#define C_ARGUMENTS_LIMIT 64
+
+/* Which functions to use for setting jump points */
+#define ecl_setjmp	@ecl_setjmp@
+#define ecl_longjmp	@ecl_longjmp@
+
+
+/* -CUT-: Everything below this mark will not be installed		*/
+/* -------------------------------------------------------------------- *
+ *	BUILD OPTIONS WHICH NEED NOT BE EXPORTED			*
+ * -------------------------------------------------------------------- */
+/*
+ * FEATURES LINKED IN:
+ */
+
 /* CLX									*/
 #undef CLX
 /* Locatives								*/
@@ -37,51 +98,21 @@
 /* Program Development Environment					*/
 #undef PDE			
 
-/* Use Boehm's garbage collector					*/
-#undef GBC_BOEHM
+/* Tcl/Tk library							*/
+#undef TK
 
 /* Allow loading dynamically linked code				*/
 #undef ENABLE_DLOPEN
 
-/* Undefine this if you do not want ECL to check for circular lists    */
+/* Undefine this if you do not want ECL to check for circular lists	*/
 #define ECL_SAFE
 
 /* Allow STREAM operations to work on arbitrary objects			*/
 #undef ECL_CLOS_STREAMS
 
-/* -------------------------------------------------------------------- *
- *	PARAMETERS							*
- * -------------------------------------------------------------------- */
-
-#define	LISP_PAGESIZE	2048	/* Page size in bytes			*/
-#define MAXPAGE	16384		/* Maximum Memory Size			*/
-#define BDSSIZE	2048		/* Size of Binding Stack		*/
-#define	BDSGETA	16		/* Safety zone of BDS			*/
-#define FRSSIZE	1024		/* Size of Frame Stack			*/
-#define	FRSGETA	16		/* Safety zone of FRS			*/
-#ifdef THREADS
-#define	CSSIZE	7500		/* Size of C Stack of each thread	*/
-#define	CSGETA	500
-#else
-#define	CSSIZE	20000		/* Size of C Stack			*/
-#define	CSGETA	4000
-#endif
-#define VSSIZE	128		/* Size of return values stack		*/
-				/* Maximum number of function arguments */
-#define CALL_ARGUMENTS_LIMIT MOST_POSITIVE_FIXNUM
-				/* Maximum number of required arguments */
-#define LAMBDA_PARAMETERS_LIMIT 64
-		/* Numb. of args. which can be passed using the C stack	*/
-#define C_ARGUMENTS_LIMIT 64
-
-#define BIGNUM_REGISTER_SIZE 16	/* Size in words of each register	*/
-
-/* -------------------------------------------------------------------- *
- *	SYSTEM FEATURES							*
- * -------------------------------------------------------------------- */
-
-#define CL_FIXNUM_TYPE 1	/* Integer type for fixnums		*/
-#define MOST_POSITIVE_FIXNUM 1	/* Positive limit for fixnums           */
+/*
+ * SYSTEM FEATURES:
+ */
 
 /* Stack grows downwards						*/
 #undef DOWN_STACK
@@ -97,3 +128,33 @@
 #undef HAVE_ISNANF
 /* float.h for epsilons, maximum real numbers, etc			*/
 #undef HAVE_FLOAT_H
+
+/*
+ * PARAMETERS:
+ */
+
+/*
+ * Memory limits for the old garbage collector.
+ */
+#define	LISP_PAGESIZE	2048	/* Page size in bytes			*/
+#define MAXPAGE	16384		/* Maximum Memory Size			*/
+
+/*
+ * The lisp environment has several stacks. These are their limits:
+ */
+#define BDSSIZE	2048		/* Size of Binding Stack		*/
+#define	BDSGETA	16		/* Safety zone of BDS			*/
+#define FRSSIZE	1024		/* Size of Frame Stack			*/
+#define	FRSGETA	16		/* Safety zone of FRS			*/
+#ifdef THREADS
+#define	CSSIZE	7500		/* Size of C Stack of each thread	*/
+#define	CSGETA	500
+#else
+#define	CSSIZE	20000		/* Size of C Stack			*/
+#define	CSGETA	4000
+#endif
+#define VSSIZE	128		/* Size of return values stack		*/
+
+/* We reserve these many bytes for computation with bignums registers	*/
+#define BIGNUM_REGISTER_SIZE 16
+
diff --git a/src/h/critical.h b/src/h/critical.h
deleted file mode 100644
index e07076c16..000000000
--- a/src/h/critical.h
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
-    critical.h  -- Mutual exclusion.
-*/
-/*
-    Copyright (c) 1990, Giuseppe Attardi.
-
-    ECoLisp is free software; you can redistribute it and/or
-    modify it under the terms of the GNU Library General Public
-    License as published by the Free Software Foundation; either
-    version 2 of the License, or (at your option) any later version.
-
-    See file '../Copyright' for full details.
-*/
-
-/*
- * SCHEDULER STOPPING
- */
-#ifdef THREADS
-#define BUSY 1
-#define CRITICAL 5
-#define ACTIVE 1
-#define INACTIVE 0
-#define SCHEDULER_INT 1
-#define ERROR_INT 2
-
-extern bool scheduler_interrupted;
-extern int critical_level;
-
-#define start_critical_section() {critical_level++;}
-
-#define end_critical_section() {  critical_level--; \
-				  if (scheduler_interrupted) \
-				    if (critical_level == 0) \
-				      interruption_handler(); }
-#endif /* THREADS */
-
-/*
- * EMPTY MACROS FOR SINGLE-THREADED CODE
- */
-#ifndef THREADS
-#define start_critical_section()
-#define end_critical_section()
-#endif /* !THREADS */
diff --git a/src/h/ecl-cmp.h b/src/h/ecl-cmp.h
index 9cb98b0f2..5128cf5d9 100644
--- a/src/h/ecl-cmp.h
+++ b/src/h/ecl-cmp.h
@@ -13,20 +13,22 @@
     See file '../Copyright' for full details.
 */
 
-#include "config.h"
-#include "machines.h"
+#include <sys/param.h>
+#include <sys/types.h>
 #include <stddef.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <setjmp.h>
 #include <math.h>
-#include <sys/types.h>
+#include "config.h"
 #include "gmp.h"
 #include "object.h"
 #include "stacks.h"
 #ifdef THREADS
-#include "lwp.h"
-#include "critical.h"
+# include "lwp.h"
+#else
+# define start_critical_section()
+# define end_critical_section()
 #endif
 #include "external.h"
 #include "eval.h"
@@ -40,12 +42,6 @@
 	if ((int *)(&narg) < cs_limit) \
 		cs_overflow()
 
-#define LINK_ARGS	&narg
 #define TRAMPOLINK(narg, vv, lk) \
 	cl_va_list args; cl_va_start(args, narg, narg, 0); \
 	return(link_call(vv, (cl_objectfn *)lk, narg, args))
-
-#define	cclosure_call	funcall
-
-#define Creturn(v)	return((VALUES(0)=(v),1))
-#define Cexit		return(0)
diff --git a/src/h/ecl.h b/src/h/ecl.h
index 8bc39cb18..805dbfbcd 100644
--- a/src/h/ecl.h
+++ b/src/h/ecl.h
@@ -15,21 +15,22 @@
 
 #include <sys/param.h>		/* includes <sys/signal.h> and <sys/types.h> */
 #include <sys/types.h>		/* for EMX */
-#include "config.h"
-#include "machines.h"
 #include <stddef.h>
 #include <stdio.h>
 #include <stdarg.h>
 #include <setjmp.h>
+#include "config.h"
 #include "gmp.h"
 #include "object.h"
 #include "stacks.h"
-#include "critical.h"
 #ifdef THREADS
 # include "lwp.h"
+#else
+# define start_critical_section()
+# define end_critical_section()
 #endif
 #ifndef _ARGS
-#define _ARGS(x) x
+# define _ARGS(x) x
 #endif
 #include "external.h"
 /*#include "ecl-inl.h"*/
diff --git a/src/h/internal.h b/src/h/internal.h
index 23d56c0de..c0a97816a 100644
--- a/src/h/internal.h
+++ b/src/h/internal.h
@@ -16,6 +16,12 @@
 extern "C" {
 #endif
 
+/* -------------------------------------------------------------------- *
+ *	FUNCTIONS, VARIABLES AND TYPES NOT FOR GENERAL USE		*
+ * -------------------------------------------------------------------- */
+
+#include "machines.h"
+
 /* all_symbols.d */
 
 extern cl_index cl_num_symbols_in_core;
@@ -54,6 +60,9 @@ extern void edit_double(int n, double d, int *sp, char *s, int *ep);
 extern void cl_setup_printer(cl_object strm);
 extern void cl_write_object(cl_object x);
 
+ /* read.d */
+#define	RTABSIZE	CHAR_CODE_LIMIT	/*  read table size  */
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/h/lwp.h b/src/h/lwp.h
index 93596d2ab..7c007db82 100644
--- a/src/h/lwp.h
+++ b/src/h/lwp.h
@@ -225,3 +225,23 @@ typedef struct pd {
 #define REALQUANTUM 100000	/*      ""      */
 
 #define STACK_SIZE (CSSIZE+CSGETA)	/* Words */
+
+/*
+ * SCHEDULER STOPPING
+ */
+#define BUSY 1
+#define CRITICAL 5
+#define ACTIVE 1
+#define INACTIVE 0
+#define SCHEDULER_INT 1
+#define ERROR_INT 2
+
+extern bool scheduler_interrupted;
+extern int critical_level;
+
+#define start_critical_section() {critical_level++;}
+
+#define end_critical_section() {  critical_level--; \
+				  if (scheduler_interrupted) \
+				    if (critical_level == 0) \
+				      interruption_handler(); }
diff --git a/src/h/machines.h b/src/h/machines.h
index 6c5cb6751..dd7b440fc 100755
--- a/src/h/machines.h
+++ b/src/h/machines.h
@@ -19,6 +19,7 @@
 #  define	stack_align(n)	(((n) + 03) & ~03)
 #endif
 
+#ifndef ecl_setjmp
 #if defined(linux)
 #  define ecl_setjmp	setjmp
 #  define ecl_longjmp	longjmp
@@ -26,6 +27,7 @@
 #  define ecl_setjmp	_setjmp
 #  define ecl_longjmp	_longjmp
 #endif
+#endif
 
 #ifdef __linux__
 #  define FILE_CNT(fp)	((fp)->_IO_read_end - (fp)->_IO_read_ptr)
diff --git a/src/h/object.h b/src/h/object.h
index 32516addd..3543590f1 100644
--- a/src/h/object.h
+++ b/src/h/object.h
@@ -19,15 +19,7 @@ extern "C" {
 #endif
 
 /*
-	Some system constants.
-*/
-
-/*
-  INV: CHAR_CODE_LIMIT is a power of two and <= MOST_POSITIVE_FIXNUM/2
-  INV: PHTABSIZE is a power of two
-  INV: ARANKLIM is of type "index"
-  INV: fixnum, cl_index are large enough to hold a pointer
-  INV: symbol and cons share cons.car = symbol.dbind, cons.cdr = symbol.sfun.
+	Integer and boolean types (see config.h)
 */
 
 #define	TRUE		1	/*  boolean true value  */
@@ -35,20 +27,9 @@ extern "C" {
 
 #define	CHAR_CODE_LIMIT	256	/*  ASCII character code limit  */
 
-#define	PHTABSIZE	512	/*  number of entries in the package hash table  */
-
-#define	ARANKLIM	64		/*  array rank limit  */
-#define	ADIMLIM		16*1024*1024	/*  array dimension limit  */
-#define	ATOTLIM		16*1024*1024	/*  array total limit  */
-
-#define	RTABSIZE	CHAR_CODE_LIMIT	/*  read table size  */
-
 #ifndef __cplusplus
 typedef int bool;
 #endif
-typedef CL_FIXNUM_TYPE cl_fixnum;
-typedef unsigned CL_FIXNUM_TYPE cl_index;
-typedef unsigned CL_FIXNUM_TYPE cl_hashkey;
 typedef unsigned char byte;
 
 /*
@@ -73,8 +54,6 @@ typedef cl_object (*cl_objectfn)(int narg, ...);
 
 /* Immediate fixnums:		*/
 #define FIXNUM_TAG		1
-#define FIXNUM_BITS		((sizeof)(cl_fixnum)/sizeof(byte)*8 - 2)
-#define MOST_NEGATIVE_FIXNUM	(-MOST_POSITIVE_FIXNUM-1)
 #define MAKE_FIXNUM(n)		((cl_object)(((cl_fixnum)(n) << 2) | FIXNUM_TAG))
 #define FIXNUM_MINUSP(n)	((cl_fixnum)(n) < 0)
 #define FIXNUM_PLUSP(n)		((cl_fixnum)(n) >= (cl_fixnum)MAKE_FIXNUM(0))
diff --git a/src/h/stacks.h b/src/h/stacks.h
index b5a7988f6..ee086bc47 100644
--- a/src/h/stacks.h
+++ b/src/h/stacks.h
@@ -201,7 +201,7 @@ extern size_t cssize;
 extern cl_object *Values;
 #else
 extern int NValues;
-extern cl_object Values[VSSIZE];
+extern cl_object Values[];
 #endif
 
 /*****************************