查找MPEG

查找原生 MPEG 包含和库

这个模块定义

MPEG_INCLUDE_DIR, where to find MPEG.h, etc.
MPEG_LIBRARIES, the libraries required to use MPEG.
MPEG_FOUND, If false, do not try to use MPEG.

也有定义，但不是一般用途

MPEG_mpeg2_LIBRARY, where to find the MPEG library.
MPEG_vo_LIBRARY, where to find the vo library.