/usr/include/x264_config.h is in libx264-dev 2:0.148.2748+git97eaef2-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 | #define X264_BIT_DEPTH 8
#define X264_GPL 1
#define X264_INTERLACED 1
#define X264_CHROMA_FORMAT 0
#define X264_VERSION " r2748 97eaef2"
#define X264_POINTVER "0.148.2748 97eaef2"
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