scons+meson: suppress spammy build warning on MacOS

Originally introduced in c7f36574 ("darwin: Suppress type
conversion warnings for GLhandleARB") to fix Bugzilla #66346 [1], this
workaround was never ported to Scons or Meson.

[1] https://bugs.freedesktop.org/66346



Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Eric Engestrom <eric.engestrom@intel.com>
Reviewed-by: Jose Fonseca <jfonseca@vmware.com>
(cherry picked from commit bf8b5de6)