release-lib.nix: remove innacurate platform groups

Removes three platform groups which imply that only linux support:

- x11Supported
- gtkSupported
- ghcSupported

replace with just linux

pkgs/top-level/release-lib.nix

@@ -157,9 +157,4 @@ rec {
   /* Common platform groups on which to test packages. */
   inherit (platforms) unix linux darwin cygwin all mesaPlatforms;
 
-  /* Platform groups for specific kinds of applications. */
-  x11Supported = linux;
-  gtkSupported = linux;
-  ghcSupported = linux;
-
 }

pkgs/top-level/release-small.nix

@@ -38,7 +38,7 @@ with import ./release-lib.nix { inherit supportedSystems; };
   dhcp = linux;
   diffutils = all;
   e2fsprogs = linux;
-  emacs25 = gtkSupported;
+  emacs25 = linux;
   enscript = all;
   file = all;
   findutils = all;
@@ -119,7 +119,7 @@ with import ./release-lib.nix { inherit supportedSystems; };
   ntp = linux;
   openssh = linux;
   openssl = all;
-  pan = gtkSupported;
+  pan = linux;
   par2cmdline = all;
   pciutils = linux;
   pdf2xml = all;