CTestCustom: Suppress warnings about rand() and srand() on OpenBSD

We don't do crypto here, so a "poor" random doesn't matter. In fact we have API
to allow people to get a repeatable sequence by setting a specific seed.
Merge topic 'openbsd-warnings' into next

f9f91fa8 CTestCustom: Suppress warnings about rand() and srand() on OpenBSD
Ninja: replace \ in LINK_PATH for MinGW
Merge topic 'ninja-win-link-path' into next

504bb62d Ninja: replace \ in LINK_PATH for MinGW