core: support make 4.00

Make 4.00 is now out, and builds work fine with it.

Change-Id: I49e36d651a7997a52270badb0e8badd975f64e8f

Conflicts:

	core/main.mk
Remove unnecessary dependencies between host and target modules.

With this change, modules introduced by LOCAL_REQUIRED_MODULES will be
split by host/target: target modules only depend on target modules and
host modules only depend on host modules.

Bug: 9303948
Change-Id: I4078a7983aa3c00e99534f3f170dfe4b66b12287