ZSTD_minCLevel
ZSTDLIB_API int ZSTD_minCLevel(void); /*!< minimum negative compression level allowed, requires v1.4.0+ */
bounds.lowerBound = ZSTD_minCLevel();
int const clampedCompressionLevel = MAX(ZSTD_minCLevel(), compressionLevel);
return ZSTD_minCLevel();