build: Add --without-gnutls configure switch
build: Add --without-gnutls configure switch

Not yet wired up in the code.

https://bugzilla.gnome.org/show_bug.cgi?id=743231

rvu95/vte,flaxandteal/gasket-vte,rvu95/vte,flaxandteal/gasket-vte,saitoha/vte-sixel,thestinger/vte-ng,saitoha/vte-sixel,flaxandteal/gasket-vte,thestinger/vte-ng,saitoha/vte-sixel,thestinger/vte-ng,rvu95/vte,flaxandteal/gasket-vte,rvu95/vte