when initial make call has subdir= explicitly set.
* sysdeps/mach/Makefile ($(patsubst
mach%,m\%h%,$(mach-before-compile))): Force subdir to mach when
calling $(MAKE).
* sysdeps/mach/hurd/Makefile ($(patsubst %,$(hurd-objpfx)hurd/%.%,auth
io fs process)): Force subdir to hurd when calling $(MAKE).
($(common-objpfx)hurd/../mach/RPC_task_get_sampled_pcs.c): Force
subdir to mach when calling $(MAKE).
7f9346e11e