handle case for clang std module detection when -print-library-module…

…-manifest-path doesn't find libc++.module.json

xmake/rules/c++/modules/modules_support/clang/compiler_support.lua

@@ -77,7 +77,7 @@ function _get_std_module_manifest_path(target)
     if print_module_manifest_flag then
         local compinst = target:compiler("cxx")
         local outdata, _ = try { function() return os.iorunv(compinst:program(), {print_module_manifest_flag}, {envs = compinst:runenvs()}) end }
-        if outdata then
+        if outdata and outdata ~= "<NOT PRESENT>" then
             return outdata:trim()
         end
     end