Avahi: Make Qt4 support optional and configurable.

svn path=/nixpkgs/trunk/; revision=10997

pkgs/development/libraries/avahi/common.nix

@@ -1,5 +1,7 @@
 sha256: args: with args;
 
+assert qt4Support -> qt4 != null;
+
 stdenv.mkDerivation rec {
   name = "avahi-" + version;
   src = fetchurl {
@@ -7,12 +9,21 @@ stdenv.mkDerivation rec {
     inherit sha256;
   };
 
-  buildInputs = [pkgconfig libdaemon dbus perl perlXMLParser glib qt4];
+  buildInputs = [pkgconfig libdaemon dbus perl perlXMLParser glib expat]
+    ++ lib.optional qt4Support qt4;
 
-  configureFlags = "--disable-qt3 --disable-gdbm --disable-gtk --disable-mono
-    --with-distro=none --enable-shared --disable-static --disable-python";
+  configureFlags = ''
+    --disable-qt3 --disable-gdbm --disable-gtk --disable-mono
+    --${if qt4Support then "enable" else "disable"}-qt4
+    --with-distro=none --enable-shared --disable-static --disable-python
+  '';
 
   meta = {
+    description = ''Avahi is a system which facilitates service discovery
+                    on a local network.  It is an implementation of the
+		    mDNS (for "Multicast DNS") and DNS-SD (for "DNS-Based
+		    Service Discovery") protocols.'';
     homepage = http://avahi.org;
+    license = "LGPLv2+";
   };
 }