--- a/configure.ac	Wed Feb  4 10:11:07 2009
+++ b/configure.ac	Wed Feb  4 10:23:07 2009
@@ -67,15 +67,15 @@
 fi
 
 if test "x$with_ipv6" != xno; then
-        CFLAGS+=" -DIPV6_SUPPORT"
+        CFLAGS="$CFLAGS -DIPV6_SUPPORT"
 fi
 
 xmlflags=`pkg-config libxml-2.0 --cflags`
-if test "$xmlflags" == ""; then
+if test "$xmlflags" = ""; then
 	AC_MSG_ERROR([libxml2 headers not found])
 fi
 
-CFLAGS+=" $xmlflags"
+CFLAGS="$CFLAGS $xmlflags"
 
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT