diff --git a/src/CHANGELOG b/src/CHANGELOG
index 1383bbe3c..e95966ec1 100644
--- a/src/CHANGELOG
+++ b/src/CHANGELOG
@@ -69,6 +69,8 @@ ECL 9.9.1:
 
  - In Solaris 8 ECL failed because it did not find inttypes.h
 
+ - When signbit() is not available, ECL now looks for existence of copysign.
+
 ;;; Local Variables: ***
 ;;; mode:text ***
 ;;; fill-column:79 ***
diff --git a/src/configure b/src/configure
index 1a6fd12f7..388bb6a62 100755
--- a/src/configure
+++ b/src/configure
@@ -12660,8 +12660,10 @@ done
 
 
 
+
 for ac_func in expf logf sqrtf cosf sinf tanf sinhf coshf tanhf \
-		floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl
+		floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl \
+                copysign
 do
 as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh`
 { $as_echo "$as_me:$LINENO: checking for $ac_func" >&5
diff --git a/src/configure.in b/src/configure.in
index 2faf86ac6..8fdbab51b 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -637,7 +637,8 @@ AC_CHECK_FUNCS( [nanosleep alarm times select setenv putenv] \
 		[gettimeofday getrusage] )
 
 AC_CHECK_FUNCS( [expf logf sqrtf cosf sinf tanf sinhf coshf tanhf] \
-		[floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl])
+		[floorf ceilf fabsf frexpf ldexpf log1p log1pf log1pl] \
+                [copysign] )
 
 AC_CHECK_FUNCS( [sched_yield uname fseeko] )