git-hub: minor clean-up

Move meta out of the way; inherit the GitHub home page from src;
`with platforms; linux` -> `platforms.linux`.

pkgs/applications/version-management/git-and-tools/git-hub/default.nix

···
 { stdenv, fetchFromGitHub, docutils, python }:
 
 let version = "0.9.0"; in
-stdenv.mkDerivation {
+stdenv.mkDerivation rec {
   name = "git-hub-${version}";
 
   src = fetchFromGitHub {
···
     owner = "sociomantic";
   };
 
-  meta = with stdenv.lib; {
-    inherit version;
-    description = "Git command line interface to GitHub";
-    longDescription = ''
-      A simple command line interface to GitHub, enabling most useful GitHub
-      tasks (like creating and listing pull request or issues) to be accessed
-      directly through the Git command line.
-    '';
-    homepage = https://github.com/sociomantic/git-hub;
-    license = licenses.gpl3Plus;
-    platforms = with platforms; linux;
-    maintainers = with maintainers; [ nckx ];
-  };
-
   buildInputs = [ python ];
   nativeBuildInputs = [ docutils ];
 
···
     # Remove inert ftdetect vim plugin and a README that's a man page subset:
     rm -r $out/share/{doc,vim}
   '';
+
+  meta = with stdenv.lib; {
+    inherit version;
+    inherit (src.meta) homepage;
+    description = "Git command line interface to GitHub";
+    longDescription = ''
+      A simple command line interface to GitHub, enabling most useful GitHub
+      tasks (like creating and listing pull request or issues) to be accessed
+      directly through the Git command line.
+    '';
+    license = licenses.gpl3Plus;
+    platforms = platforms.linux;
+    maintainers = with maintainers; [ nckx ];
+  };
 }