remove unused environment function
remove unused environment function

The script dir is never really used since meson --internal handles this.
The last remaining use of the raw script dir got removed in commit
522392e7553823e6b3ac38cadc4fbee72eae9540.

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