nixpkgs: no parallel builds for mono 4.4

See #32386 -- while Mono in general should build correctly with parallel
building, it seems the 4.4 branch has broken.

Instead, allow parallel build support to be overridden by individual
versions, and default to true.

Signed-off-by: Austin Seipp <aseipp@pobox.com>

pkgs/development/compilers/mono/4.4.nix

@@ -4,4 +4,5 @@ callPackage ./generic.nix (rec {
   inherit Foundation libobjc;
   version = "4.4.2.11";
   sha256 = "0cxnypw1j7s253wr5hy05k42ghgg2s9qibp10kndwnp5bv12q34h";
+  buildParallel = false; # see #32386 -- parallel building broken on 4.4
 })

pkgs/development/compilers/mono/generic.nix

@@ -1,4 +1,11 @@
-{ stdenv, fetchurl, bison, pkgconfig, glib, gettext, perl, libgdiplus, libX11, callPackage, ncurses, zlib, withLLVM ? false, cacert, Foundation, libobjc, python, version, sha256 }:
+{ stdenv, fetchurl, bison, pkgconfig, glib, gettext, perl, libgdiplus, libX11
+, callPackage, ncurses, zlib
+, cacert, Foundation, libobjc, python
+
+, version, sha256
+, withLLVM ? false
+, buildParallel ? true
+}:
 
 let
   llvm     = callPackage ./llvm.nix { };
@@ -40,7 +47,7 @@ stdenv.mkDerivation rec {
   # The file /nix/store/xxx-mono-2.4.2.1/lib/mscorlib.dll is an invalid CIL image
   dontStrip = true;
 
-  enableParallelBuilding = true;
+  enableParallelBuilding = buildParallel;
 
   # We want pkg-config to take priority over the dlls in the Mono framework and the GAC
   # because we control pkg-config