- having `$TERMUX_PREFIX/bin` in `$PATH` severely breaks cross-compilations
- on-device builds already have `$TERMUX_PREFIX/bin` in `$PATH` at all times, so editing it is not necessary for on-device builds
- for similar reasons, also prevent `GNUstep.sh` from putting `$TERMUX_PREFIX/lib` in `$LD_LIBRARY_PATH`