(C++ modules support) fix warnings for std module

Author: Arthapz

xmake/rules/c++/modules/clang/support.lua

@@ -258,7 +258,7 @@ end
 
 function get_stdmodules(target)
 
-    if target:policy("build.c++.modules.std") then
+    if not target:policy("build.c++.modules.std") then
         return
     end
     local cpplib = _get_cpplibrary_name(target)
@@ -282,14 +282,14 @@ function get_stdmodules(target)
             -- dont be greedy and don't enable stdc++ std module support for llvm < 19
             local clang_version = get_clang_version(target)
             if clang_version and semver.compare(clang_version, "19.0") >= 0 then
-                return import(".gcc.support").get_stdmodules(target, {dont_warn = true})
+                return import(".gcc.support").get_stdmodules(target)
             end
         elseif cpplib == "msstl" then
             -- msstl std module file is not compatible with llvm < 19
             local clang_version = get_clang_version(target)
             if clang_version and semver.compare(clang_version, "19.0") >= 0 then
                 local toolchain = target:toolchain("llvm") or target:toolchain("clang") or target:toolchain("clang-cl")
-                return import(".msvc.support").get_stdmodules(target, {dont_warn = false, toolchain = toolchain})
+                return import(".msvc.support").get_stdmodules(target, {toolchain = toolchain})
             end
         end
     end

xmake/rules/c++/modules/gcc/support.lua

@@ -166,8 +166,7 @@ function _get_std_module_manifest_path(target)
     end
 end
 
-function get_stdmodules(target, opt)
-    opt = opt or {}
+function get_stdmodules(target)
     if not target:policy("build.c++.modules.std") then
         return
     end
@@ -187,9 +186,7 @@ function get_stdmodules(target, opt)
             return std_module_files
         end
     end
-    if not opt.dont_warn then
-        wprint("std and std.compat modules not found! maybe try to add --sdk=<PATH/TO/LLVM> or install libc++")
-    end
+    wprint("std and std.compat modules not found! maybe try to add --sdk=<PATH/TO/LLVM> or install libc++")
 end
 
 function get_bmi_extension()

xmake/rules/c++/modules/msvc/support.lua

@@ -136,9 +136,7 @@ function get_stdmodules(target, opt)
             end
         end
     end
-    if not opt.dont_warn then
-        wprint("std and std.compat modules not found! disabling them for the build")
-    end
+    wprint("std and std.compat modules not found! disabling them for the build")
 end
 
 function get_bmi_extension()