src/vte.c: Make multiple calls to set_background_transparent() and set_background_image() do the right thing.
src/vte.c: Make multiple calls to set_background_transparent() and set_background_image() do the right thing.

flaxandteal/gasket-vte,flaxandteal/gasket-vte,rvu95/vte,pjm0616/vte,rvu95/vte,pjm0616/vte,jessevdk/vte,asivokon/vte-fx,asivokon/vte-fx,thestinger/vte-ng,rvu95/vte,aligo/vte,flaxandteal/gasket-vte,aligo/vte,asivokon/vte-fx,thestinger/vte-ng,pjm0616/vte,gloob/vte-copy,asivokon/vte-fx,gloob/vte-copy,jessevdk/vte,saitoha/vte-sixel,jessevdk/vte,thestinger/vte-ng,saitoha/vte-sixel,jessevdk/vte,gloob/vte-copy,saitoha/vte-sixel,flaxandteal/gasket-vte,aligo/vte,rvu95/vte