Override ucrtbase.def (x64 only for now)

Auto-generated via MinGW-w64 gendef tool, based on ucrtbase.dll
v10.0.17134.319.

Author: kinke

windows/mingw/buildsdk.d

@@ -232,8 +232,10 @@ void main(string[] args)
     if (args.length > 3)
         outDir = args[3];
 
+    const archDir = "lib" ~ (x64 ? "64" : "32");
     copyDefs(buildPath(mingwDir, "mingw-w64-crt", "lib-common"), outDir);
-    copyDefs(buildPath(mingwDir, "mingw-w64-crt", "lib" ~ (x64 ? "64" : "32")), outDir);
+    copyDefs(buildPath(mingwDir, "mingw-w64-crt", archDir), outDir);
+    copyDefs(buildPath("def-overrides", archDir), outDir);
 
     defs2implibs(outDir);