--- gcc-11.1.0/libstdc++-v3/configure.host
+++ gcc-11.1.0/libstdc++-v3/configure.host
@@ -272,11 +272,11 @@
     ;;
   mingw32*)
     case "$host" in
-      *-w64-*)
+      *)
         os_include_dir="os/mingw32-w64"
         error_constants_dir="os/mingw32-w64"
         ;;
-      *)
+      NOTREACHED)
         os_include_dir="os/mingw32"
         error_constants_dir="os/mingw32"
         ;;