ffmpeg update to june 23 version which fixes mp4 crash on still frames with 3...

source/patched-ffmpeg-mt/libavutil/internal.h

Index: source/patched-ffmpeg-mt/libavutil/internal.h
===================================================================
--- source/patched-ffmpeg-mt/libavutil/internal.h	(revision 50820)
+++ source/patched-ffmpeg-mt/libavutil/internal.h	(working copy)
@@ -46,6 +46,12 @@
 #endif
 #endif
 
+
+/**
+ * Marks a variable as used and prevents the compiler from optimizing it away.
+ * This is usefull for asm that accesses varibles in ways that the compiler doesnt
+ * understand
+ */
 #ifndef attribute_used
 #if AV_GCC_VERSION_AT_LEAST(3,1)
 #    define attribute_used __attribute__((used))
@@ -196,6 +202,30 @@
 #   define NULL_IF_CONFIG_SMALL(x) x
 #endif
 
+/**
+ * Create a non default alias for a function with specified version.
+ * This is needed when symbols are moved from a lib to a dependancy of the lib
+ * because the gnu linker as of 2010 is buggy and fails to dynamicaly link if a symbol
+ * is not found in the lib in which it was during link time with enabled versioning
+ * even if a correctly versioned and matching symbol exists in another lib and
+ * even if it did find that would it not contain an explicit check to fail
+ */
+#if HAVE_SYMVER_ASM_LABEL
+#   define FF_SYMVER(type, name, args, ver)                     \
+    type ff_##name args __asm__ (EXTERN_PREFIX #name "@" ver);  \
+    type ff_##name args
+#elif HAVE_SYMVER_GNU_ASM
+#   define FF_SYMVER(type, name, args, ver)                             \
+    __asm__ (".symver ff_" #name "," EXTERN_PREFIX #name "@" ver);      \
+    type ff_##name args;                                                \
+    type ff_##name args
+#endif
+
+/**
+ * Returns NULL if a threading library has not been enabled.
+ * Used to disable threading functions in AVCodec definitions
+ * when not needed.
+ */
 #if HAVE_THREADS
 #   define ONLY_IF_THREADS_ENABLED(x) x
 #else