6648 illumos build should be explicit about C standards

@@ -81,12 +81,12 @@
 
 #
 # Create assym.h
 #
 $(GENASSYM): $(GENASSYM_SRC)
-        $(NATIVECC) $(ALWAYS_DEFS) $(GENASSYM_DEFS) $(NATIVE_INC_PATH) \
-           -o $@ $(GENASSYM_SRC)
+        $(NATIVECC) $(NATIVE_CFLAGS) $(ALWAYS_DEFS) $(GENASSYM_DEFS) \
+           $(NATIVE_INC_PATH) -o $@ $(GENASSYM_SRC)
 
 $(ASSYM_H): $(OFFSETS_SRC) $(PLATFORM_OFFSETS_SRC) $(GENASSYM)
         $(OFFSETS_CREATE) <$(OFFSETS_SRC) >$@
         $(OFFSETS_CREATE) <$(PLATFORM_OFFSETS_SRC) >>$@
         $(GENASSYM) >>$@