[FFmpeg-devel] Do not define API_IMPORTS for libx264 and libx265

[anonymous.maarten at gmail.com]

When building ffmpeg on Visual Studio,
libavcodec/libx264.c and libavcodec/libx265.c assume that
ffmpeg is linked to a dynamic libx264 and libx265 library.

Instead, this information is delivered by pkg-config.

Linking ffmpeg to a static libx264 causes LNK4049 warnings to be emitted.

Because warnings can obscure bugs, I propose to remove these lines and let pkg-config handle this.

Best regards

(First patch using git send-mail)