diff --git a/ANNOUNCE b/ANNOUNCE
index f5a966d24..a5230daf7 100644
--- a/ANNOUNCE
+++ b/ANNOUNCE
@@ -374,6 +374,8 @@ Version 1.6.0beta23 [June 4, 2012]
   Made fixes for new optimization warnings from gcc 4.7.0. The compiler
     performs an optimization which is safe; however it then warns about it.
     Changing the type of 'palette_number' in pngvalid.c removes the warning.
+  Do not depend upon a GCC feature macro being available for use in generating
+    the linker mapfile symbol prefix.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/CHANGES b/CHANGES
index 1727ffa41..1b16cf213 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4125,6 +4125,8 @@ Version 1.6.0beta23 [June 4, 2012]
   Made fixes for new optimization warnings from gcc 4.7.0. The compiler
     performs an optimization which is safe; however it then warns about it.
     Changing the type of 'palette_number' in pngvalid.c removes the warning.
+  Do not depend upon a GCC feature macro being available for use in generating
+    the linker mapfile symbol prefix.
 
 Send comments/corrections/commendations to png-mng-implement at lists.sf.net
 (subscription required; visit
diff --git a/configure.ac b/configure.ac
index d95c231ad..1db2efdb7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -185,9 +185,9 @@ AM_CONDITIONAL(HAVE_LD_VERSION_SCRIPT, test "$have_ld_version_script" = "yes")
 if test "$have_ld_version_script" = "yes"; then
     AC_MSG_CHECKING([for symbol prefix])
     SYMBOL_PREFIX=`echo "PREFIX=__USER_LABEL_PREFIX__" \
-                   | ${CPP-${CC-gcc} -E} - 2>&1 \
-                   | ${EGREP-grep} "^PREFIX=" \
-                   | ${SED-sed} "s:^PREFIX=::"`
+                  | ${CPP-${CC-gcc} -E} - 2>&1 \
+                  | ${EGREP-grep} "^PREFIX=" \
+                  | ${SED-sed} -e "s:^PREFIX=::" -e "s:__USER_LABEL_PREFIX__::"`
     AC_SUBST(SYMBOL_PREFIX)
     AC_MSG_RESULT($SYMBOL_PREFIX)
 fi