Hello, In trying to bootstrap a minimal environment, I ended up trying to run a configure script using just busybox (specifically, Debian's busybox-static). This almost worked, except that the configure script used diff several times. configure just uses diff for its exit code, to check for identical files. The version of busybox-static in Debian doesn't provide diff, but does provide cmp.
This issue manifested as configure complaining that it could not find a usable grep, due to the test for grep using diff. As far as I can tell, configure scripts never actually need the output of diff; they just need a program that can detect whether files differ and provide an appropriate exit status for use in conditionals. Rather than unconditionally using diff, please consider detecting and using an appropriate $ac_files_identical program; either diff or cmp would work. For that matter, such detection would also provide a good opportunity to check for a working diff -q or cmp -s, which run faster since they can stop at the first difference and don't have to generate output. - Josh Triplett
