FreeBSD doesn't have acl/libacl.h. We can easily fix this problem by replacing acl/libacl.h with sys/acl.h, which works on both FreeBSD and Linux.
FreeBSD doesn't have libacl because ACL functions are already available in libc. Linking with -lacl causes the check to fail because libacl cannot be found.
Created attachment 136596 [details] [review]
build-sys: Enable ACL support on FreeBSD
sys/acl.h works on both FreeBSD and Linux, so we should use it instead
of acl/libacl.h, which only works on Linux.
FreeBSD puts ACL functions in libc, so we should check whether ACL
functions are available in libc before doing the check with -lacl.
but it looks good to me, so I'll push it soon.
Pushed as https://cgit.freedesktop.org/spice/spice-gtk/commit/?id=0f588eb3fdfc17394c7d5bdf23cb1d0ea6e3c190