xf86_input_multitouch: remove

The source repo doesn't exist and it hasn't been touched in 8 years.
There is also no module to interface with it in NixOS.

pkgs/os-specific/linux/xf86-input-multitouch/default.nix

@@ -1,48 +0,0 @@
-{ stdenv
-, fetchgit
-, mtdev
-, pixman
-, xorg
-, libpciaccess
-}:
-
-stdenv.mkDerivation {
-  name = "xf86-input-multitouch-20110312";
-
-  src = fetchgit {
-    url = http://bitmath.org/git/multitouch.git;
-    rev = "4d87c041f6a232aa30528d70d4b9946d1824b4ed";
-    sha256 = "1jh52d3lkmchn5xdbz4qn50d30nild1zxvfbvwwl2rbmphs5ww6y";
-  };
-
-  # Configuration from http://bitmath.org/code/multitouch/
-  confFile = ''
-    Section "InputClass"
-        MatchIsTouchpad "true"
-        Identifier "Multitouch Touchpad"
-        Driver "multitouch"
-    EndSection
-  '';
-
-  buildInputs = with xorg; [
-    mtdev xorgproto libpciaccess libxcb
-  ];
-
-  buildPhase = ''
-    make INCLUDE="$NIX_CFLAGS_COMPILE -I${xorg.xorgserver.dev}/include/xorg -I${pixman}/include/pixman-1 -Iinclude"
-  '';
-
-  installPhase = ''
-    make DESTDIR="$out" LIBDIR="lib" install
-    mkdir -p $out/include/xorg
-    echo -n "$confFile" > $out/include/xorg/10-multitouch.conf
-  '';
-
-  meta = {
-    homepage = http://bitmath.org/code/multitouch/;
-
-    description = "Brings multitouch gestures to the Linux desktop";
-
-    license = stdenv.lib.licenses.gpl2;
-  };
-}

pkgs/top-level/aliases.nix

@@ -477,6 +477,7 @@ mapAliases ({
   xf86_video_nouveau = xorg.xf86videonouveau; # added 2015-09
   xf86_input_mtrack = throw ("xf86_input_mtrack has been removed from nixpkgs as it hasn't been maintained"
     + "and is broken. Working alternatives are libinput and synaptics.");
+  xf86_input_multitouch = throw "xf86_input_multitouch has been removed from nixpkgs."; # added 2020-01-20
   xlibs = xorg; # added 2015-09
   xpraGtk3 = xpra; # added 2018-09-13
   youtubeDL = youtube-dl;  # added 2014-10-26

pkgs/top-level/all-packages.nix

@@ -17217,8 +17217,6 @@ in
 
   xf86_input_cmt = callPackage ../os-specific/linux/xf86-input-cmt { };
 
-  xf86_input_multitouch = callPackage ../os-specific/linux/xf86-input-multitouch { };
-
   xf86_input_wacom = callPackage ../os-specific/linux/xf86-input-wacom { };
 
   xf86_video_nested = callPackage ../os-specific/linux/xf86-video-nested { };