avcodec: Disable new iterate API for ossfuzz

A few days ago ossfuzz stoped testing new FFmpeg as it run out of diskspacee

https://oss-fuzz-build-logs.storage.googleapis.com/index.html

An alternative would be to revert the API.

This changes for example
-rwxr-x--- 1 michael michael 144803654 May 14 12:54 tools/target_dec_ac3_fixed_fuzzer*
to
-rwxr-x--- 1 michael michael  30333852 May 14 12:51 tools/target_dec_ac3_fixed_fuzzer*

Which should massively decrease space requirements
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavcodec/allcodecs.c

@@ -760,7 +760,12 @@ extern AVCodec ff_vp9_cuvid_decoder;
 extern AVCodec ff_vp9_mediacodec_decoder;
 extern AVCodec ff_vp9_vaapi_encoder;
 
+// The iterate API is not usable with ossfuzz due to the excessive size of binaries created
+#if CONFIG_OSSFUZZ
+extern AVCodec * codec_list[];
+#else
 #include "libavcodec/codec_list.c"
+#endif
 
 static AVOnce av_codec_static_init = AV_ONCE_INIT;
 static void av_codec_init_static(void)

tools/target_dec_fuzzer.c

@@ -56,6 +56,11 @@
 
 int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size);
 
+AVCodec * codec_list[] = {
+    NULL,
+    NULL
+};
+
 static void error(const char *err)
 {
     fprintf(stderr, "%s", err);
@@ -144,6 +149,7 @@ int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
 #define DECODER_SYMBOL0(CODEC) ff_##CODEC##_decoder
 #define DECODER_SYMBOL(CODEC) DECODER_SYMBOL0(CODEC)
         extern AVCodec DECODER_SYMBOL(FFMPEG_DECODER);
+        codec_list[0] = &DECODER_SYMBOL(FFMPEG_DECODER);
         avcodec_register(&DECODER_SYMBOL(FFMPEG_DECODER));
 
         c = &DECODER_SYMBOL(FFMPEG_DECODER);