On 05/24/2011 08:41 PM, Josh Triplett wrote: >> That's in conflict with the current GNU Coding Standards, which states >> that a program can blindly assume the existence of diff on $PATH. >> >> 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. Autoconf can still be patched to support diff-less systems, but since such systems don't comply with the GCS, there's no guarantee that some other part of the build system will crop up as the next culprit. I think your efforts may be better directed to fixing busybox first. > > On a related note, I just checked the configure script for GNU diffutils > 3.0, and it depends on having a working diff program. :) And that's fine, according to the GCS. If GCS changes, then we'll fix diffutils to build without requiring pre-installed diff. >> 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? It seems like you'd want to add a new macro at the autoshell level, maybe: AS_COMPARE_IFELSE([file1], [file2], [action-if-same], [action-if-different]) and make all existing clients of diff be reworked to call AS_COMPARE_IFELSE, and put the smarts of deciding between diff and cmp in the setup for AS_COMPARE_IFELSE. -- Eric Blake eblake@xxxxxxxxxx +1-801-349-2682 Libvirt virtualization library http://libvirt.org
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