Fixed the bug caused by the default standard of Macos compiler not c++11

packages/g/gtest/xmake.lua

@@ -18,12 +18,14 @@ package("gtest")
         io.writefile("xmake.lua", [[
             target("gtest")
                 set_kind("static")
+                set_languages("cxx11")
                 add_files("googletest/src/gtest-all.cc")
                 add_includedirs("googletest/include", "googletest")
                 add_headerfiles("googletest/include/(**.h)")
 
             target("gmock")
                 set_kind("static")
+                set_languages("cxx11")
                 add_files("googlemock/src/gmock-all.cc")
                 add_includedirs("googlemock/include", "googlemock", "googletest/include", "googletest")
                 add_headerfiles("googlemock/include/(**.h)")