diff --git a/configure.in b/configure.in
index 7e92c3a..78ee479 100644
--- a/configure.in
+++ b/configure.in
@@ -39,6 +39,15 @@ m4_defun([AC_PROG_F77],[])
 
 AM_PROG_LIBTOOL
 
+dnl See if the compiler supports -std=gnu99 since some math
+dnl functions need it (aka round())
+AC_MSG_CHECKING(whether $CC accepts -std=gnu99)
+cc_supports_gnu99="yes"
+save_CPPFLAGS="$CPPFLAGS"
+CPPFLAGS="$CPPFLAGS -std=gnu99"
+AC_TRY_COMPILE(,,,[cc_supports_gnu99="no";CPPFLAGS="$save_CPPFLAGS"])
+AC_MSG_RESULT($cc_supports_gnu99)
+
 if test "x${bindir}" = 'x${exec_prefix}/bin'; then
   if test "x${exec_prefix}" = "xNONE"; then
     if test "x${prefix}" = "xNONE"; then