Propagate USE_HOST_MUSL to Soong

Support enabling musl in Make builds with USE_HOST_MUSL=true.  Only
modules defined in Soong will use musl, but that's almost all host
modules.

Bug: 195988762
Test: m USE_HOST_MUSL=true adb
Change-Id: Ia88f6e20b302d86f2241877b017aebe218d968cf
diff --git a/core/config.mk b/core/config.mk
index acdf15e..d049dca 100644
--- a/core/config.mk
+++ b/core/config.mk
@@ -1004,6 +1004,14 @@
 BOARD_PREBUILT_HIDDENAPI_DIR ?=
 .KATI_READONLY := BOARD_PREBUILT_HIDDENAPI_DIR
 
+ifdef USE_HOST_MUSL
+  ifneq (,$(or $(BUILD_BROKEN_USES_BUILD_HOST_EXECUTABLE),\
+               $(BUILD_BROKEN_USES_BUILD_HOST_SHARED_LIBRARY),\
+               $(BUILD_BROKEN_USES_BUILD_HOST_STATIC_LIBRARY)))
+    $(error USE_HOST_MUSL can't be set when native host builds are enabled in Make with BUILD_BROKEN_USES_BUILD_HOST_*)
+  endif
+endif
+
 # ###############################################################
 # Set up final options.
 # ###############################################################