try to fix unnamed_symbol_lookup test for mac

Author: eronnen

lldb/test/API/python_api/unnamed_symbol_lookup/Makefile

@@ -10,8 +10,13 @@ else
 STRIP_COMMAND = $(STRIP) --keep-symbol=main
 endif
 
-a.out.stripped:
-	$(STRIP_COMMAND) -o a.out.stripped a.out
+a.out.stripped: a.out
+ifeq "$(OS)" "Darwin"
+	echo "_main" > keep_symbols.txt
+	$(STRIP) -s keep_symbols.txt -o a.out.stripped a.out
+else
+	$(STRIP) --keep-symbol=main -o a.out.stripped a.out
+endif
 
 ifneq "$(CODESIGN)" ""
 	$(CODESIGN) -fs - a.out.stripped