Index: configure
===================================================================
--- ffmpeg.orig/configure	(revision 25082)
+++ ffmpeg/configure	(working copy)
@@ -2222,7 +2222,7 @@
 fi
 
 add_cppflags -D_ISOC99_SOURCE -D_POSIX_C_SOURCE=200112
-check_cflags -std=c99
+check_cflags -std=gnu99
 check_cc -D_FILE_OFFSET_BITS=64 <<EOF && add_cppflags -D_FILE_OFFSET_BITS=64
 #include <stdlib.h>
 EOF
@@ -2230,7 +2230,7 @@
 #include <stdlib.h>
 EOF
 
-check_host_cflags -std=c99
+check_host_cflags -std=gnu99
 
 case "$arch" in
     alpha|ia64|mips|parisc|sparc)