* util/grub.d/30_os-prober.in: New script. Use `os-prober' and
`linux-boot-prober' (if installed) to detect other operating
systems which are installed on the computer and add them to
the boot menu.
* conf/common.rmk: Build and install 30_os-prober.
All executable files in this directory are processed in shell expansion order. 00_*: Reserved for 00_header. 10_*: Native boot entries. 20_*: Third party apps (e.g. memtest86+). The number namespace in-between is configurable by system installer and/or administrator. For example, you can add an entry to boot another OS as 01_otheros, 11_otheros, etc, depending on the position you want it to occupy in the menu; and then adjust the default setting via /etc/default/grub.