Fix Windows build.

MSVC 2013 doesn't implement C++11 alignas. Use __declspec instead.

Change-Id: I48a402d56d734f3f2c434b4bdf2a5bc671c50225
Reviewed-on: https://boringssl-review.googlesource.com/5421
Reviewed-by: Adam Langley <agl@google.com>
1 file changed