Add support for LOCAL_SRC_FILES_<extra> to build_bc_lib.mk.

Change-Id: I7f857b86bf0bfd165de461fe2036f48ae0ac9128
diff --git a/driver/runtime/build_bc_lib_internal.mk b/driver/runtime/build_bc_lib_internal.mk
index 478ab30..efb6bb6 100644
--- a/driver/runtime/build_bc_lib_internal.mk
+++ b/driver/runtime/build_bc_lib_internal.mk
@@ -52,8 +52,11 @@
 endif
 rs_debug_runtime:=
 
-c_sources := $(filter %.c,$(LOCAL_SRC_FILES))
-ll_sources := $(filter %.ll,$(LOCAL_SRC_FILES))
+bc_src_files := $(LOCAL_SRC_FILES)
+bc_src_files += $(LOCAL_SRC_FILES_$(TARGET_$(LOCAL_2ND_ARCH_VAR_PREFIX)ARCH)) $(LOCAL_SRC_FILES_$(my_32_64_bit_suffix))
+
+c_sources := $(filter %.c,$(bc_src_files))
+ll_sources := $(filter %.ll,$(bc_src_files))
 
 c_bc_files := $(patsubst %.c,%.bc, \
     $(addprefix $(intermediates)/, $(c_sources)))