build: Clean up legacy signal creation leftovers
build: Clean up legacy signal creation leftovers

pjm0616/vte,jessevdk/vte,thestinger/vte-ng,flaxandteal/gasket-vte,thestinger/vte-ng,pjm0616/vte,jessevdk/vte,saitoha/vte-sixel,saitoha/vte-sixel,jessevdk/vte,rvu95/vte,rvu95/vte,flaxandteal/gasket-vte,flaxandteal/gasket-vte,saitoha/vte-sixel,thestinger/vte-ng,rvu95/vte,pjm0616/vte,jessevdk/vte,flaxandteal/gasket-vte,rvu95/vte