use libtool as ar for xcode_11_1
"werror_mode": "all",
"c_compiler": "$(CLANG)/usr/bin/clang",
"cxx_compiler": "$(CLANG)/usr/bin/clang++",
- "ar": "$(CLANG)/usr/bin/ar",
+ "ar": "$(CLANG)/usr/bin/libtool",
"inplace_tools": true,
"gcc_version": "8.0",
"dwarf_tool": {
