environment: simplify handling of native files with no cross files
environment: simplify handling of native files with no cross files

Instead of treating native files as always being for the build machine,
and then copying them to the host machine, treat them as for the build
machine only when a cross file is also present

pexip/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,pexip/meson,pexip/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,jpakkane/meson,QuLogic/meson,mesonbuild/meson,QuLogic/meson,QuLogic/meson,jpakkane/meson,QuLogic/meson,jpakkane/meson,pexip/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,QuLogic/meson,jpakkane/meson,mesonbuild/meson,QuLogic/meson,mesonbuild/meson,mesonbuild/meson,QuLogic/meson,mesonbuild/meson,jpakkane/meson,pexip/meson,pexip/meson,mesonbuild/meson,QuLogic/meson,QuLogic/meson