Fixing breakpad on old linux kernel

Try to read the trace's registers by PTRACE_GETREGS if kernel doesn't support PTRACE_GETREGSET.

Bug:

Change-Id: I881f3a868789747ca217f22a93370c6914881f9a
Reviewed-on: https://chromium-review.googlesource.com/484479
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Cr-Mirrored-From: https://chromium.googlesource.com/breakpad/breakpad
Cr-Mirrored-Commit: 67649c61853108eb0c29703f6ff0db42e9d69f10
2 files changed