First, fix a collision with the Point type from MacTypes.h, which was
reported on Slack, 2022-07-31: https://cpplang.slack.com/archives/C2X659D1B/p1659284691275889
Second, rename the meta:: namespace to TestMeta::. OSX's "/usr/include/ncurses.h"
defines a meta function, and is (for some reason) included in
"<SDK>/usr/include/module.modulemap", so that identifier is
off-limits for us to use in anything that compiles with -fmodules:
libcxx/test/support/type_algorithms.h:16:11: error: redefinition of 'meta' as different kind of symbol namespace meta { ^ <SDK>/usr/include/ncurses.h:603:28: note: previous definition is here extern NCURSES_EXPORT(int) meta (WINDOW *,bool); /* implemented */ ^