add stdc++_static for gcc

xmake/modules/core/tools/gcc.lua

@@ -185,6 +185,38 @@ function nf_vectorext(self, extension)
     return maps[extension]
 end
 
+-- has -static-libstdc++?
+function _has_static_libstdcxx(self)
+    local has_static_libstdcxx = _g._HAS_STATIC_LIBSTDCXX
+    if has_static_libstdcxx == nil then
+        if self:has_flags("-static-libstdc++ -Werror", "ldflags", {flagskey = "gcc_static_libstdcxx"}) then
+            has_static_libstdcxx = true
+        end
+        has_static_libstdcxx = has_static_libstdcxx or false
+        _g._HAS_STATIC_LIBSTDCXX = has_static_libstdcxx
+    end
+    return has_static_libstdcxx
+end
+
+-- make the runtime flag
+function nf_runtime(self, runtime, opt)
+    opt = opt or {}
+    local maps
+    local kind = self:kind()
+    if not self:is_plat("android") then -- we will set runtimes in android ndk toolchain
+        maps = maps or {}
+        if kind == "ld" or kind == "sh" then
+            local target = opt.target
+            if target and target.sourcekinds and table.contains(table.wrap(target:sourcekinds()), "cxx") then
+                if runtime:endswith("_static") and _has_static_libstdcxx(self) then
+                    maps["stdc++_static"] = "-static-libstdc++"
+                end
+            end
+        end
+    end
+    return maps and maps[runtime]
+end
+
 -- make the language flag
 function nf_language(self, stdname)
 

xmake/toolchains/mingw/xmake.lua

@@ -18,23 +18,14 @@
 -- @file        xmake.lua
 --
 
--- define toolchain
 toolchain("mingw")
-
-    -- set homepage
+    set_kind("standalone")
     set_homepage("http://www.mingw.org/")
     set_description("Minimalist GNU for Windows")
+    set_runtimes("stdc++_static", "stdc++_shared")
 
-    -- mark as standalone toolchain
-    set_kind("standalone")
-
-    -- check toolchain
     on_check("check")
-
-    -- on load
     on_load(function (toolchain)
-
-        -- imports
         import("core.project.config")
 
         -- get cross