Remove obsolete OSX instructions
Remove obsolete OSX instructions

drewet/gtk,gkoz/rust-gnome-cairo,gkoz/gtk-rs-glib,gkoz/gtk-rs-cairo,drewet/gtk,mitaa/gtk,rust-gnome/cairo,rtsuk/cairo,Susurrus/glib,nicokoch/glib,LordSentox/gtk,gkoz/rust-gnome-glib,EPashkin/rust-gnome-gtk,Susurrus/gtk,gkoz/rust-gnome-gtk,rust-gnome/glib,gkoz/gtk-rs-gtk,gkoz/rust-gnome-gtk,Susurrus/gtk,insanebits/gtk,rust-gnome/gtk,gkoz/gtk-rs-pango,mitaa/gtk,rust-gnome/gtk,gkoz/gtk-rs-gtk,daa84/gtk,EPashkin/rust-gnome-gtk,daa84/gtk,insanebits/gtk,EPashkin/rust-gnome-glib,LordSentox/gtk