diff --git a/libs/iksemel/configure.ac b/libs/iksemel/configure.ac
index 49d8621777..403725a80d 100644
--- a/libs/iksemel/configure.ac
+++ b/libs/iksemel/configure.ac
@@ -83,12 +83,12 @@ AC_ARG_ENABLE(64,
 
 if test "x${ax_cv_c_compiler_vendor}"  =  "xsun" ; then
     if test "${enable_64}" = "yes"; then
-        CFLAGS="$CFLAGS -xc99=all -mt -m64 -lgpg-error"
-        CXXFLAGS="$CXXFLAGS -xc99=all -mt -m64 -lgpg-error"
+        CFLAGS="$CFLAGS -mt -m64 -lgpg-error"
+        CXXFLAGS="$CXXFLAGS -mt -m64 -lgpg-error"
 	SUNFLAGS="-xc99=all -mt -m64 -lgpg-error"
     else 
-	CFLAGS="$CFLAGS -xc99=all -mt -lgpg-error"
-	CXXFLAGS="$CXXFLAGS -xc99=all -mt -lgpg-error"
+	CFLAGS="$CFLAGS  -mt -lgpg-error"
+	CXXFLAGS="$CXXFLAGS -mt -lgpg-error"
 	SUNFLAGS="-xc99=all -mt -lgpg-error"
     fi
 fi