INT64_C poorly (re)defined (Patch #2033)
A comment in modules/highgui/src/ffmpeg_codecs.hpp states
"some versions of FFMPEG assume a C99 compiler, and don't define INT64_C". Good.
However, the (re)definition provided is really poor, and probably only works on (some ?) linux systems. For instance, this breaks on netbsd where the opencv code redefine the INT64_C to an empty string, which is obviously wrong.
I suggest using the attached patch.