minor release.sh fixes and tweaks
minor release.sh fixes and tweaks

- pre-install bmake for further (future) base/pkgsrc disentanglement          
- print url properly for pre-install source                                   
- correct <minix/sys_config.h> source location                                



veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi,veritas-shine/minix3-rpi