GObject: warn on use of deprecated properties
GObject: warn on use of deprecated properties

By default G_PARAM_DEPRECATED means absolutely nothing.  We only emit a
warning if G_ENABLE_DIAGNOSTIC is set to '1' and then, only on sets.

Turn the logic on its head: emit the warning by default, unless
G_ENABLE_DIAGNOSTIC is set to 0.  In order to avoid a torrent of output, only
emit a warning once per property name.

https://bugzilla.gnome.org/show_bug.cgi?id=732184

MathieuDuponchelle/glib,krichter722/glib,krichter722/glib,lukasz-skalski/glib,krichter722/glib,tchakabam/glib,MathieuDuponchelle/glib,cention-sany/glib,endlessm/glib,lukasz-skalski/glib,endlessm/glib,ieei/glib,endlessm/glib,tamaskenez/glib,johne53/MB3Glib,mzabaluev/glib,endlessm/glib,lukasz-skalski/glib,tamaskenez/glib,mzabaluev/glib,gale320/glib,tamaskenez/glib,lukasz-skalski/glib,mzabaluev/glib,krichter722/glib,cention-sany/glib,ieei/glib,cention-sany/glib,tchakabam/glib,Distrotech/glib,endlessm/glib,Distrotech/glib,tamaskenez/glib,gale320/glib,ieei/glib,ieei/glib,johne53/MB3Glib,tchakabam/glib,MathieuDuponchelle/glib,cention-sany/glib,johne53/MB3Glib,johne53/MB3Glib,tamaskenez/glib,tchakabam/glib,Distrotech/glib,mzabaluev/glib,johne53/MB3Glib,Distrotech/glib,MathieuDuponchelle/glib,johne53/MB3Glib,MathieuDuponchelle/glib,lukasz-skalski/glib,tchakabam/glib,cention-sany/glib,Distrotech/glib,gale320/glib,gale320/glib,krichter722/glib,gale320/glib,ieei/glib,mzabaluev/glib