Put in defense against gcc -ffast-math.

configure.in

@@ -1,5 +1,5 @@
 dnl Process this file with autoconf to produce a configure script.
-dnl $Header: /cvsroot/pgsql/configure.in,v 1.209 2002/09/17 04:27:41 momjian Exp $
+dnl $Header: /cvsroot/pgsql/configure.in,v 1.210 2002/09/20 18:38:57 petere Exp $
 dnl
 dnl Developers, please strive to achieve this order:
 dnl
@@ -253,12 +253,21 @@ if test "$enable_debug" = yes && test "$ac_cv_prog_cc_g" = yes; then
   CFLAGS="$CFLAGS -g"
 fi
 AC_MSG_NOTICE([using CFLAGS=$CFLAGS])
+
 # Check if the compiler still works with the template settings
 AC_MSG_CHECKING([whether the C compiler still works])
 AC_TRY_LINK([], [return 0;],
   [AC_MSG_RESULT(yes)],
   [AC_MSG_RESULT(no)
    AC_MSG_ERROR([cannot proceed])])
+
+# Defend against gcc -ffastmath
+if test "$GCC" = yes; then
+AC_TRY_COMPILE([], [@%:@ifdef __FAST_MATH__
+choke me
+@%:@endif], [], [AC_MSG_ERROR([do not put -ffast-math in CFLAGS])])
+fi
+
 AC_PROG_CPP
 AC_SUBST(GCC)