warnings are errors

Originally committed as revision 2057 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/Makefile

@@ -6,7 +6,7 @@ include ../config.mak
 
 VPATH=$(SRC_PATH)/libavformat
 
-CFLAGS= $(OPTFLAGS) -Wall -g -I.. -I$(SRC_PATH) -I$(SRC_PATH)/libavcodec -DHAVE_AV_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE
+CFLAGS= $(OPTFLAGS) -Wall -g -I.. -I$(SRC_PATH) -I$(SRC_PATH)/libavcodec -DHAVE_AV_CONFIG_H -D_FILE_OFFSET_BITS=64 -D_LARGEFILE_SOURCE -D_GNU_SOURCE -Werror
 
 OBJS= utils.o cutils.o allformats.o
 PPOBJS=