Don't specify CMAKE_CXX_STANDARD anymore either.

This is for consistency with commit a022cc0.

Change-Id: Iaded0d669d821b06bdb57d70b519205426643f91
Reviewed-on: https://code-review.googlesource.com/c/re2/+/59870
Reviewed-by: Perry Lorier <perryl@google.com>
Reviewed-by: Paul Wankadia <junyer@google.com>
1 file changed