add udev rules, but make them optional (default == off)

svn path=/nixpkgs/trunk/; revision=4643

pkgs/misc/linuxwacom/10-wacom.rules

@@ -0,0 +1,3 @@
+# udev rule to create /dev/input/wacomN for wacom tablets
+
+KERNEL="event*", SYSFS{manufacturer}="WACOM", NAME="input/%k", SYMLINK="input/wacom%e"

pkgs/misc/linuxwacom/builder.sh

@@ -0,0 +1,12 @@
+source $stdenv/setup
+
+postInstall() {
+  if test -n "$udevSupport"; then
+    ensureDir $out/etc/udev/rules.d
+    cp $udevRules $out/etc/udev/rules.d/10-wacom.rules
+  fi
+}
+
+postInstall=postInstall
+
+genericBuild

pkgs/misc/linuxwacom/default.nix

@@ -1,10 +1,13 @@
-{stdenv, fetchurl, libX11, libXi}:
+{stdenv, fetchurl, libX11, libXi, udevSupport ? false}:
 
 stdenv.mkDerivation {
   name = "linuxwacom-0.7.2";
+  builder = ./builder.sh;
   src = fetchurl {
     url = http://surfnet.dl.sourceforge.net/sourceforge/linuxwacom/linuxwacom-0.7.2.tar.bz2;
     md5 = "3f6290101d5712a24097243ca9f092ed";
   };
   buildInputs = [libX11 libXi];
+  udevRules = ./10-wacom.rules;
+  inherit udevSupport;
 }