tree 2eb5fda228209f04c524bfa765a87f7f0a2ad312
parent 2df4b755f5748a0e1f316b6c253cfafd2d1e357e
author James Zern <jzern@google.com> 1654102208 -0700
committer James Zern <jzern@google.com> 1654284319 +0000

compiler_flags.cmake: fix flag detection w/cmake 3.17-3.18.2

Between 3.17.0 and 3.18.2 check_cxx_compiler_flag() sets a normal
variable at parent scope while check_cxx_source_compiles() continues to
set an internal cache variable, so we unset both to avoid the failure /
success state persisting between checks.

Change-Id: I4c9d63d89113d4ce9dc33a937b95df2e9acfce1a
(cherry picked from commit 1c69d568cabbceec8e09904ae513acb1d63358ac)