Disable riscv64 dependency on bcc and ld.mc

riscv64 can't build the device version of bcc and ld.mc due to a
dependency on an old version of LLVM, but they are listed in
base_system.mk which can't add them conditionally based on the target
architecture.  Add a hack to base_system.mk to silence the warning
that the host-only modules are listed in PRODUCT_PACKAGES.  This
can be removed once renderscript is removed from the platform.

Test: lunch aosp_riscv64-userdebug && m
Change-Id: I8efd769a34b110dfb838f7016e029369cb9a0f01
diff --git a/core/main.mk b/core/main.mk
index 3866037..f6f48e7 100644
--- a/core/main.mk
+++ b/core/main.mk
@@ -1345,6 +1345,13 @@
                   $(if $(ALL_MODULES.$(m).INSTALLED),\
                     $(if $(filter-out $(HOST_OUT_ROOT)/%,$(ALL_MODULES.$(m).INSTALLED)),,\
                       $(m))))
+    ifeq ($(TARGET_ARCH),riscv64)
+      # HACK: riscv64 can't build the device version of bcc and ld.mc due to a
+      # dependency on an old version of LLVM, but they are listed in
+      # base_system.mk which can't add them conditionally based on the target
+      # architecture.
+      _host_modules := $(filter-out bcc ld.mc,$(_host_modules))
+    endif
     $(call maybe-print-list-and-error,$(sort $(_host_modules)),\
       Host modules should be in PRODUCT_HOST_PACKAGES$(comma) not PRODUCT_PACKAGES)
   endif