nx-libs: minor fixes

* Add an alias with a deprecation warning for `nxproxy` to avoid an
  immediate breaking change.

* Use the default shell used in the build environment (`stdenv.shell`)
  for patching. This shell is in the environment and thus used to patch
  scripts using `patchShebangs`. The shell is referenced as `stdenv.shell`
  in Makefiles to patch the remaining occurrences of `/bin/bash` in the
  build environment.

pkgs/tools/X11/nx-libs/default.nix

@@ -20,8 +20,8 @@ stdenv.mkDerivation rec {
   enableParallelBuilding = true;
 
   postPatch = ''
-    find . -type f -executable -exec sed -i 's|^#!/bin/bash$|#!${bash}/bin/bash|g' {} \;
-    find . -type f -name Makefile -exec sed -i 's|^\(SHELL:=\)/bin/bash$|\1${bash}/bin/bash|g' {} \;
+    patchShebangs .
+    find . -type f -name Makefile -exec sed -i 's|^\(SHELL:=\)/bin/bash$|\1${stdenv.shell}|g' {} \;
     ln -s libNX_X11.so.6.3.0
   '';
 

pkgs/top-level/aliases.nix

@@ -209,6 +209,7 @@ mapAliases ({
   nilfs_utils = nilfs-utils; # added 2018-04-25
   nmap_graphical = nmap-graphical;  # added 2017-01-19
   nologin = shadow; # added 2018-04-25
+  nxproxy = lib.warn "nxproxy will be removed soon, use `nx-libs` instead" nx-libs; # added 2019-02-15
   opencascade_oce = opencascade; # added 2018-04-25
   opencl-icd = ocl-icd; # added 2017-01-20
   openexr_ctl = ctl; # added 2018-04-25

pkgs/top-level/all-packages.nix

@@ -4519,12 +4519,6 @@ in
 
   nylon = callPackage ../tools/networking/nylon { };
 
-  nxproxy = throw ''
-    nxproxy has been replaced by nx-libs which builds both nxagent and nxproxy.
-    This is because the nx-libs upstream repository can not build nxagent
-    without also building nxproxy. See nixpkgs#55723
-  '';
-
   nzbget = callPackage ../tools/networking/nzbget { };
 
   oathToolkit = callPackage ../tools/security/oath-toolkit { inherit (gnome2) gtkdoc;  };