only run HAVE_SETNETGRENT_RETURN check if setnetgrent found

Sam James requested to merge thesamesam/polkit:meson-fixes into master

This avoids a spurious -Wimplicit-function-declaration warning on e.g. musl where we already checked for setnetgrent and found it's not present.

i.e. This avoids trying to use a function in a subsequent test when we already know it doesn't exist. There's no point trying to probe its properties.

Signed-off-by: Sam James

Merge request reports