Index: trunk/psphot/configure.ac
===================================================================
--- trunk/psphot/configure.ac	(revision 6147)
+++ trunk/psphot/configure.ac	(revision 6310)
@@ -19,7 +19,7 @@
   [AS_HELP_STRING(--enable-optimize,enable compiler optimization)],
   [AC_MSG_RESULT(compile optimization enabled)
-   CFLAGS="${CFLAGS=} -O2"],
+   CFLAGS="-O2"],
   [AC_MSG_RESULT([compile optimization disabled])
-   CFLAGS="${CFLAGS=} -O0 -g"]
+   CFLAGS="-O0 -g"]
 )