[SCM] libav/experimental: Append the user CPPFLAGS value to the CPPFLAGS used for compilation, rather than prepend it.

[siretart at users.alioth.debian.org]

The following commit has been merged in the experimental branch:
commit 04a803bef44e1929d3556c74c68e66b5124d7a3a
Author: Stefano Sabatini <stefano.sabatini-lala at poste.it>
Date:   Sun Jul 12 15:50:25 2009 +0000

    Append the user CPPFLAGS value to the CPPFLAGS used for compilation,
    rather than prepend it.
    
    This way there is the guarantee that the included headers are those in
    the FFmpeg sources, rather than pre-installed headers referenced by
    the user CPPFLAGS.
    
    Originally committed as revision 19416 to svn://svn.ffmpeg.org/ffmpeg/trunk

diff --git a/common.mak b/common.mak
index 02c7303..9cc7357 100644
--- a/common.mak
+++ b/common.mak
@@ -18,7 +18,7 @@ endif
 
 ALLFFLIBS = avcodec avdevice avfilter avformat avutil postproc swscale
 
-CPPFLAGS += -DHAVE_AV_CONFIG_H -I$(BUILD_ROOT_REL) -I$(SRC_PATH)
+CPPFLAGS := -DHAVE_AV_CONFIG_H -I$(BUILD_ROOT_REL) -I$(SRC_PATH) $(CPPFLAGS)
 
 %.o: %.c
 	$(CC) $(CPPFLAGS) $(CFLAGS) $(LIBOBJFLAGS) -c $(CC_O) $<

-- 
Libav/FFmpeg packaging