Fix build on macos 10.15 with clang 11.0.

We no longer need the -Wno-extended-offsetof or -Wno-invalid-offsetof
compiler options, since the nonstandard uses of offsetof() were
fixed (see job003619), so they can just be removed.

mps/code/mps.xcodeproj/project.pbxproj

@@ -5606,7 +5606,6 @@
 					"-Wmissing-prototypes",
 					"-Wmissing-variable-declarations",
 					"-Wnested-externs",
-					"-Wno-extended-offsetof",
 					"-Wpointer-arith",
 					"-Wshadow",
 					"-Wstrict-aliasing=2",
@@ -6055,7 +6054,6 @@
 					"-Wmissing-prototypes",
 					"-Wmissing-variable-declarations",
 					"-Wnested-externs",
-					"-Wno-extended-offsetof",
 					"-Wpointer-arith",
 					"-Wshadow",
 					"-Wstrict-aliasing=2",
@@ -6123,7 +6121,6 @@
 					"-Wmissing-prototypes",
 					"-Wmissing-variable-declarations",
 					"-Wnested-externs",
-					"-Wno-extended-offsetof",
 					"-Wpointer-arith",
 					"-Wshadow",
 					"-Wstrict-aliasing=2",

mps/configure

@@ -3374,7 +3374,7 @@ CFLAGS_GC="-ansi -pedantic -Wall -Werror -Wpointer-arith \
            -Wstrict-prototypes -Wmissing-prototypes \
            -Winline -Waggregate-return -Wnested-externs \
            -Wcast-qual -Wstrict-aliasing=2 -O -g3 -pthread"
-CFLAGS_LL="$CFLAGS_GC -Wno-invalid-offsetof"
+CFLAGS_LL="$CFLAGS_GC"
 
 # Make sure we can run config.sub.
 $SHELL "$ac_aux_dir/config.sub" sun4 >/dev/null 2>&1 ||

mps/configure.ac

@@ -36,7 +36,7 @@ CFLAGS_GC="-ansi -pedantic -Wall -Werror -Wpointer-arith \
            -Wstrict-prototypes -Wmissing-prototypes \
            -Winline -Waggregate-return -Wnested-externs \
            -Wcast-qual -Wstrict-aliasing=2 -O -g3 -pthread"
-CFLAGS_LL="$CFLAGS_GC -Wno-invalid-offsetof"
+CFLAGS_LL="$CFLAGS_GC"
 
 AC_CANONICAL_HOST
 AC_MSG_CHECKING([target platform])