Add native FreeBSD building functionality (#35)

This commit enables native building on FreeBSD through Cmake + ninja.

Reviewed-on: https://git.eden-emu.dev/eden-emu/eden/pulls/35
Reviewed-by: crueter <crueter@eden-emu.dev>
Co-authored-by: SDK-Chan <sdkchan@eden-emu.dev>
Co-committed-by: SDK-Chan <sdkchan@eden-emu.dev>

src/video_core/host1x/ffmpeg/ffmpeg.h

@@ -25,7 +25,13 @@ extern "C" {
 #include <libavcodec/avcodec.h>
 #include <libavutil/opt.h>
 #include <libavutil/pixdesc.h>
+
+// Works quite fine, and omits the hacky ffmpeg building for now...
+#if defined(__FreeBSD__)
+#include <libavcodec/codec.h>
+#else
 #include <libavcodec/codec_internal.h>
+#endif
 
 #if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop