Support .asm being compiled by yasm targeted for x86.

Change-Id: Icd6626a082facf920b0e49e2fbe8861e94400552
diff --git a/core/definitions.mk b/core/definitions.mk
index 5d76285..746becf 100644
--- a/core/definitions.mk
+++ b/core/definitions.mk
@@ -1039,6 +1039,16 @@
 $(transform-d-to-p)
 endef
 
+# YASM compilation
+define transform-asm-to-o
+@mkdir -p $(dir $@)
+$(hide) $(YASM) \
+    $(addprefix -I , $(PRIVATE_C_INCLUDES)) \
+    -f elf32 -m x86 \
+    $(PRIVATE_ASFLAGS) \
+    -o $@ $<
+endef
+
 ###########################################################
 ## Commands for running gcc to compile an Objective-C file
 ## This should never happen for target builds but this