Do not disable incompatible-pointer-types-discards-qualifiers

Do not disable incompatible-pointer-types-discards-qualifiers

This reverts commit b3710e9a2af402a2b620de570b062294e11190eb.

That check is very valuable for our code, but it causes issue with glib >=
2.67.0 when building with clang.

The reason is a combination of two commits in glib, firstly fdda405b6b1b which
adds a g_atomic_pointer_{set,get} variants that enforce stricter type
checking (by removing an extra cast) for compilers that support __typeof__, and
commit dce24dc4492d which effectively enabled the new variant of glib's atomic
code for clang.  This will not be necessary when glib's issue #600 [0] (8 years
old) is fixed.  Thankfully, MR #1719 [1], which is supposed to deal with this
issue was opened 3 weeks ago, so there is a slight sliver of hope.

[0] https://gitlab.gnome.org/GNOME/glib/-/issues/600
[1] https://gitlab.gnome.org/GNOME/glib/-/merge_requests/1719

Signed-off-by: Martin Kletzander <mkletzan@redhat.com>