Stable-mask webkit USE flag for alpha

Webkit itself will likely never be stable on alpha, so mask the USE flag
globally. Remove package-individual masks.

profiles/arch/alpha/package.use.stable.mask

@@ -36,19 +36,12 @@
 # net-fs/libnfs lacks alpha keyword, bug #551576
 gnome-base/gvfs nfs
 
-# Tobias Klausmann <[email protected]> (29 Jul 2015)
-# Mask webkit so the dep can stay ~alpha forever
->=x11-libs/wxGTK-3.0.2.0-r1 webkit
-
 # Pacho Ramos <[email protected]> (02 Jul 2014)
 # Mask due Gnome3 not going to be stabilized on this arch
-dev-util/geany-plugins devhelp markdown webkit
+dev-util/geany-plugins devhelp markdown
 >=gnome-base/gnome-desktop-2.32.1-r2 license-docs
 gnome-base/gvfs google
-mail-client/balsa webkit
-media-gfx/gimp webkit
 media-plugins/gst-plugins-meta modplug
 >=x11-libs/gtk+-3.12.2 cloudprint
-net-libs/libproxy webkit
 >=net-libs/webkit-gtk-2.4 geoloc
 x11-libs/gksu gnome

profiles/arch/alpha/use.stable.mask

@@ -5,6 +5,11 @@
 # This file requires eapi 5 or later. New entries go on top.
 # Please use the same syntax as in use.mask
 
+# Tobias Klausmann <[email protected]> (17 Mar 2016)
+# Webkit itself is enormous (~13h compile+test on our fastest dev machine), so
+# it will remain not-stable forever. Mask the USE flag accordingly.
+webkit
+
 # Pacho Ramos <[email protected]> (17 Apr 2014)
 # Dropped stable keywords after the discussion caused by
 # Gnome 3.8/3.10 stabilization on this arch