[evolution] Put compiler warning flags in AM_CPPFLAGS instead of CFLAGS.

[Matthew Barnes <mbarnes src gnome org>]

commit 914ec21b499162ad71be4bfbb3e6ea8198042b2b
Author: Matthew Barnes <mbarnes redhat com>
Date:   Fri Oct 23 23:36:55 2009 -0400

    Put compiler warning flags in AM_CPPFLAGS instead of CFLAGS.

 configure.ac |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b1c2c39..4d74d46 100644
--- a/configure.ac
+++ b/configure.ac
@@ -92,7 +92,9 @@ dnl	-Wmissing-format-attribute
 dnl	-Wshadow
 dnl	-Wformat-nonliteral
 
-CFLAGS="$CFLAGS $WARNING_FLAGS"
+AM_CPPFLAGS="$WARNING_FLAGS"
+AC_SUBST(AM_CPPFLAGS)
+
 LDFLAGS="$LDFLAGS -Wl,--no-undefined"
 
 AC_CANONICAL_HOST