__has_feature is a clang extension. GCC errors out on the test.
Define a helper macro to make the code working with other compilers.
Bug: chromium:819294
Change-Id: I359150acd4700e65b4faf5f297b29664c18000d3
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/4418706
Reviewed-by: Joshua Peraza <jperaza@chromium.org>
Commit-Queue: Joshua Peraza <jperaza@chromium.org>
Reviewed-by: Ben Hamilton <benhamilton@google.com>