LZ4_compress_generic_validated() : * inlined, to ensure branches are decided at compilation time. * The following conditions are presumed already

The "double dictionary" mode, for use with e.g. ring buffers: the first part * of the dictionary is passed as prefix, and the second via dictStart +

LZ4_memcpy_using_offset() presumes : * - dstEnd >= dstPtr + MINMATCH * - there is at least 12 bytes available to write after dstEnd */

keep it working in UBSAN