On Tue, May 24, 2011 at 12:43:58PM -0600, Eric Blake wrote: > On 05/24/2011 11:41 AM, Josh Triplett wrote: > > 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. > > That's in conflict with the current GNU Coding Standards, which states > that a program can blindly assume the existence of diff on $PATH. > Either we need to tighten GCS to forbid unqualified use of diff, or > improve the busybox setup to start providing diff as expected by GCS, or > both. > > http://www.gnu.org/prep/standards/standards.html#Utilities-in-Makefiles I would propose both: busybox can support diff if compiled for it, but at the same time I'd like to support systems without a diff program, as long as they have *something* to compare two files. On a related note, I just checked the configure script for GNU diffutils 3.0, and it depends on having a working diff program. :) > > 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. > > > > Does this seem like a reasonable addition to autoconf? (If it falls > > under "OK, if someone provides a patch", I can do so.) > > Certainly okay if someone provides a patch. It's not my highest > priority, but I like the idea if it improves portability of a configure > script. Does it seem reasonable to modify existing macros that use diff to depend on a check for an appropriate program? - Josh Triplett _______________________________________________ Autoconf mailing list Autoconf@xxxxxxx https://lists.gnu.org/mailman/listinfo/autoconf
