Add MZ_TRY_EXTFLONUMS to OpenBSD.

Also add an error to unsupported platforms (copied from FreeBSD).

Merge to 5.3.4
(cherry picked from commit ac42864f3bf316ead1672bec1fc953b1169bd193)
fix problem with switchable-button tool tip

Closes PR 12562

Merge to v5.3.4
(cherry picked from commit ff580c212c150e91822c2cdeb8be0f86caa366bf)
win64: JIT stack-trace repair

Relevant to PR 13702

Merge to 5.3.4
(cherry picked from commit 5887d7808cf8711057046405febc9267f56f2e24)