Prepare for clang+mingw windows builds

Use $(prefix)CLANG_SUPPORTED from Soong to control whether to use clang
for host builds or not. It's fairly general, but I only expect it to be
used to so that Windows builds can be switched between GCC and Clang
with a single switch.

Also separate native-host-cross from native-host so that it's easier to
build all possible windows modules.

Bug: 69933068
Test: m native-host-cross
Test: switch clang on and off, grep w64.*g++ out/build-aosp_arm.ninja
Change-Id: I205c5bc6739b72a539ece935381107ec1dd5bd48

core/base_rules.mk

@@ -667,7 +667,7 @@ endif
 
 
 ifdef j_or_n
-$(j_or_n) $(h_or_t) $(j_or_n)-$(h_or_t) : $(my_checked_module)
+$(j_or_n) $(h_or_t) $(j_or_n)-$(h_or_hc_or_t) : $(my_checked_module)
 ifneq (,$(filter $(my_module_tags),tests))
 $(j_or_n)-$(h_or_t)-tests $(j_or_n)-tests $(h_or_t)-tests : $(my_checked_module)
 endif

core/binary.mk

@@ -387,9 +387,9 @@ endif
 # clang is enabled by default for host builds
 # enable it unless we've specifically disabled clang above
 ifdef LOCAL_IS_HOST_MODULE
-    ifeq ($($(my_prefix)OS),windows)
+    ifneq ($($(my_prefix)CLANG_SUPPORTED),true)
         ifeq ($(my_clang),true)
-            $(error $(LOCAL_MODULE_MAKEFILE): $(LOCAL_MODULE): Clang is not yet supported for windows binaries)
+            $(call pretty-error,Clang is not yet supported for $($(my_prefix)OS) binaries)
         endif
         my_clang := false
     else