Detect blocked signal installation by sanitizers
Detect blocked signal installation by sanitizers

Sanitizers can prevent the installation of signal handlers, but
sigaction would still return 0 (for success). Detect this by checking
the installed signal handler via a second call to sigaction.

R=f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org

Bug: chromium:1328749
Change-Id: I62a5777379ec5c6b1ca2d5a62e7cd3fb8ed1437b
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/3702302
Reviewed-by: Mark Mentovai <f1b5a91d4d6ad523f2610114591c007e75d15084@chromium.org>
Commit-Queue: Clemens Backes <d6c5e8ed8251c01f440df5442e89f611e093e642@chromium.org>

chromium/crashpad,chromium/crashpad,chromium/crashpad