m4: fix local ffmpeg and avcodec function conflict

[giuliobenetti]

Autotools miss avcodec function check. This is due to linker library list order, -ldrm is appended too early respect to -lavutil. This results in missing drm library functions for avcodec functions:

• drmGetVersion()
• drmFreeVersion() So these functions:
• avcodec_get_context_defaults3
• avcodec_open2
• avcodec_encode_video2 can't link correctly during check and they seem not to be present. Then macros HAVE_FUN_avcodec_* are not defined in mediastreamer-config.h So local avcodec functions conflict with real avcodec library functions.

In acinclude.m4 file, swap $FFMPEG_LIBS and -lavutil if avcodec is found.

Signed-off-by: Giulio Benetti [email protected]

[giuliobenetti]

This is valid during static linking only