docs: add pkgconfig to cross file example
docs: add pkgconfig to cross file example

trhd/meson,jeandet/meson,MathieuDuponchelle/meson,jeandet/meson,QuLogic/meson,pexip/meson,QuLogic/meson,becm/meson,trhd/meson,becm/meson,becm/meson,becm/meson,pexip/meson,QuLogic/meson,becm/meson,ernestask/meson,trhd/meson,QuLogic/meson,pexip/meson,ernestask/meson,trhd/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,ernestask/meson,ernestask/meson,thiblahute/meson,trhd/meson,trhd/meson,pexip/meson,jpakkane/meson,thiblahute/meson,pexip/meson,MathieuDuponchelle/meson,jpakkane/meson,becm/meson,MathieuDuponchelle/meson,thiblahute/meson,jeandet/meson,becm/meson,thiblahute/meson,QuLogic/meson,mesonbuild/meson,jeandet/meson,ernestask/meson,thiblahute/meson,thiblahute/meson,jeandet/meson,mesonbuild/meson,becm/meson,ernestask/meson,pexip/meson,mesonbuild/meson,jpakkane/meson,ernestask/meson,trhd/meson,MathieuDuponchelle/meson,trhd/meson,jpakkane/meson,pexip/meson,jpakkane/meson,thiblahute/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,QuLogic/meson,MathieuDuponchelle/meson,QuLogic/meson,MathieuDuponchelle/meson,MathieuDuponchelle/meson,trhd/meson,jeandet/meson,thiblahute/meson,jpakkane/meson,becm/meson,jeandet/meson,MathieuDuponchelle/meson,jpakkane/meson,thiblahute/meson,QuLogic/meson,pexip/meson,ernestask/meson,jeandet/meson,becm/meson,QuLogic/meson,mesonbuild/meson,mesonbuild/meson,MathieuDuponchelle/meson,mesonbuild/meson,ernestask/meson,mesonbuild/meson,mesonbuild/meson,jeandet/meson