Add basic musl support to make

There are still devices that set BUILD_BROKEN_USES_BUILD_HOST_* and
build host modules in Make.  Add basic support for building against
libc_musl in Make when USE_HOST_MUSL is set.

Bug: 258535366
Test: build a host tool defined in Android.mk file in internal branch
Change-Id: I9150be749bbeaac2ac5a33b2cf915004aa3033df
diff --git a/core/host_executable_internal.mk b/core/host_executable_internal.mk
index 0cf62a4..2ff9ff2 100644
--- a/core/host_executable_internal.mk
+++ b/core/host_executable_internal.mk
@@ -39,6 +39,21 @@
 endif
 my_libdir :=
 
+my_crtbegin :=
+my_crtend :=
+my_libcrt_builtins :=
+ifdef USE_HOST_MUSL
+  my_crtbegin := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtbegin_dynamic)
+  my_crtend := $(SOONG_$(LOCAL_2ND_ARCH_VAR_PREFIX)HOST_OBJECT_libc_musl_crtend)
+  my_libcrt_builtins := $($(LOCAL_2ND_ARCH_VAR_PREFIX)$(my_prefix)LIBCRT_BUILTINS)
+  $(LOCAL_BUILT_MODULE): PRIVATE_LDFLAGS += -Wl,--no-dynamic-linker
+endif
+
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTBEGIN := $(my_crtbegin)
+$(LOCAL_BUILT_MODULE): PRIVATE_CRTEND := $(my_crtend)
+$(LOCAL_BUILT_MODULE): PRIVATE_LIBCRT_BUILTINS := $(my_libcrt_builtins)
+$(LOCAL_BUILT_MODULE): $(my_crtbegin) $(my_crtend) $(my_libcrt_builtins)
+
 $(LOCAL_BUILT_MODULE): $(all_objects) $(all_libraries) $(CLANG_CXX)
 	$(transform-host-o-to-executable)