supercollider: use bash from nixpkgs for popen

pkgs/development/interpreters/supercollider/default.nix

···
-{ lib, stdenv, mkDerivation, fetchurl, cmake
+{ lib, stdenv, mkDerivation, fetchurl, cmake, runtimeShell
 , pkg-config, alsa-lib, libjack2, libsndfile, fftw
 , curl, gcc, libXt, qtbase, qttools, qtwebengine
 , readline, qtwebsockets, useSCEL ? false, emacs
···
     # add support for SC_DATA_DIR and SC_PLUGIN_DIR env vars to override compile-time values
     ./supercollider-3.12.0-env-dirs.patch
   ];
+
+  postPatch = ''
+    substituteInPlace common/sc_popen.cpp --replace '/bin/sh' '${runtimeShell}'
+  '';
 
   strictDeps = true;