Index: trunk/psastro/configure.ac
===================================================================
--- trunk/psastro/configure.ac	(revision 12164)
+++ trunk/psastro/configure.ac	(revision 14186)
@@ -1,4 +1,4 @@
 dnl Process this file with autoconf to produce a configure script.
-AC_PREREQ(2.59)
+AC_PREREQ(2.61)
 
 AC_INIT([psastro], [0.9.0], [ipp-support@ifa.hawaii.edu])
@@ -13,5 +13,5 @@
 AC_LANG(C)
 AC_GNU_SOURCE
-AC_PROG_CC
+AC_PROG_CC_C99
 AC_PROG_INSTALL
 AC_PROG_LIBTOOL
@@ -188,5 +188,5 @@
 dnl Set CFLAGS for build
 IPP_STDOPTS
-CFLAGS="${CFLAGS=} -Wall -Werror -std=c99"
+CFLAGS="${CFLAGS=} -Wall -Werror"
 echo "PSASTRO_CFLAGS: $PSASTRO_CFLAGS"
 echo "PSASTRO_LIBS: $PSASTRO_LIBS"