Handle garbage in environment more gracefully when setting vsenv
Handle garbage in environment more gracefully when setting vsenv

Environment line may not contain '=' and thus fail to decompose into a
key/value pair.

mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,pexip/meson,pexip/meson,pexip/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson