[gnome-photos] build: Use AM_CFLAGS for warning flags instead of AM_CPPFLAGS

[Debarshi Ray <debarshir src gnome org>]

commit 55457afe8a640a430fc9d8f18abc04a99fcd2614
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Apr 28 16:56:01 2014 +0200

    build: Use AM_CFLAGS for warning flags instead of AM_CPPFLAGS
    
    ... because those are meant for the compiler, not the preprocessor.

 src/Makefile.am |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/Makefile.am b/src/Makefile.am
index dc3c945..069d510 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -279,10 +279,13 @@ AM_CPPFLAGS = \
        $(LIBEXIF_CFLAGS) \
        $(LIBRSVG_CFLAGS) \
        $(TRACKER_CFLAGS) \
-       $(WARN_CFLAGS) \
        -I$(top_srcdir)/libgd \
        $(NULL)
 
+AM_CFLAGS = \
+       $(WARN_CFLAGS) \
+       $(NULL)
+
 gnome_photos_LDFLAGS =
 
 gnome_photos_LDADD = \