common: hoist x265_mdate above using namespace x265

I do not understand why, but this fixes cli linkage on Mac
y4m: disable file reader thread on frame header errors

Prevents deadlocks from malformed Y4M files
input: add missing carriage returns from error log messages
pixel: sse_sp[LUMA_12x16] fails tests on clang, disable it
cmake: use system native stdint.h and getopt if they are found
Merge with stable