lang/gcc11: Fix build on FreeBSD 15

Update files/patch-libphobos_libdruntime_core_sys_freebsd_config.d patch
to take into account FreeBSD 15.

See also commit 929ca7ff802f14a2852122678d0c1b9e5a89be22 which already
did the same thing for lang/gcc11-devel. The new patch is indeed a copy
of the one in lang/gcc11-devel.