rustc: remove broken flag for musl

It builds!

pkgs/development/compilers/rust/rustc.nix

@@ -192,8 +192,5 @@ in stdenv.mkDerivation rec {
     maintainers = with maintainers; [ madjar cstrahan globin havvy ];
     license = [ licenses.mit licenses.asl20 ];
     platforms = platforms.linux ++ platforms.darwin;
-    # rustc can't generate binaries for dynamically linked Musl.
-    # https://github.com/NixOS/nixpkgs/issues/179242
-    broken = stdenv.targetPlatform.isMusl && !stdenv.targetPlatform.isStatic;
   };
 }