I just helped someone debug an issue today where their configure run was getting weird results, because they had called './configure CFLAGS="-Wall -Werror -O0 -g"', and the -Werror was causing several tests to guess wrong. This issue has repeatedly come up on this list, and our advice has always been "don't use -Werror during configure; save it for 'make'". In fact, we even have examples to point to on how to write a configure script that will probe whether -Werror works and add it automatically at make time without also polluting the rest of the configure run (such as via coreutils' ./configure --enable-gcc-warnings, coupled with Makefile.am snippets to add -Werror to AM_CFLAGS as appropriate). For packages that already take care to separate out -Werror handling, I'm thinking it might be worthwhile to have a macro that would emit a warning at ./configure time if CC is detected as gcc, and CFLAGS contains -Werror, since this usually won't have the desired results. Of course, it would need to be a new macro (we don't want to change the behavior of configure to add a warning without explicit request by package maintainers), but it seems like something that enough packages would like to be worth including in the next autoconf release. It seems like such a macro should be called after AC_PROG_CC (need to know if the compiler is gcc). Thoughts? Does my idea make sense? What would a good macro name be? AC_PROG_CC_SUSPICIOUS_CFLAGS AC_PROG_CC_NO_WERROR -- Eric Blake eblake@xxxxxxxxxx +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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