lib: Factor in tiny bit of meta.platform checking

I need it in stdenv and release-lib, so that seems motivation enough.

pkgs/stdenv/generic/check-meta.nix

@@ -173,10 +173,8 @@ let
     else "key '${k}' is unrecognized; expected one of: \n\t      [${lib.concatMapStringsSep ", " (x: "'${x}'") (lib.attrNames metaTypes)}]";
   checkMeta = meta: if shouldCheckMeta then lib.remove null (lib.mapAttrsToList checkMetaAttr meta) else [];
 
-  checkPlatform = attrs: let
-      raw = attrs.meta.platforms;
-      uniform = map (x: if builtins.isString x then { system = x; } else { parsed = x; }) raw;
-    in lib.any (pat: lib.matchAttrs pat hostPlatform) uniform;
+  checkPlatform = attrs:
+    lib.any (lib.meta.platformMatch hostPlatform) attrs.meta.platforms;
 
   # Check if a derivation is valid, that is whether it passes checks for
   # e.g brokenness or license.