When included inside an `extern "C"` block, this causes build failures
that look something like:
/usr/include/c++/10/type_traits:2930:3: error: template with C linkage
2930 | template<typename _Fn, typename... _Args>
| ^~~~~~~~
../../disas/arm-a64.cc:20:1: note: ‘extern "C"’ linkage started here
20 | extern "C" {
| ^~~~~~~~~~
Commit 4273c43902a7e6b22cea0041436ee5715c93be76 made this opt in for
projects which are defining `GLIB_VERSION_MIN_REQUIRED`, but the include
of `<type_traits>` via `gmacros.h` was not included in this. If we move
the include out to the places where `glib_typeof` is called, we can make
it covered by this macro too, and save a few consumers from FTBFSing.
That also means that, if you don't want to fix your use of the headers,
and as long as this version is sufficient for you, a quick workaround is
to define `GLIB_VERSION_MIN_REQUIRED` to `GLIB_VERSION_2_66` or lower.
Suggested by Simon McVittie.
Alternative to: https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1935
Fixes: https://gitlab.gnome.org/GNOME/glib/-/issues/2331