autoreconf assumes that it can pass --warnings=<anything> to both the tools maintained in Autoconf (autoconf, autoheader, etc.) and to the tools maintained in Automake (automake, aclocal, etc.) However, the set of warnings categories defined in autoconf’s lib/Autom4te/ChannelDefs.pm has diverged from the set defined in automake’s lib/Automake/ChannelDefs.pm. (These were clearly once the same file, but have not been in sync since before 2003!) In particular, autoconf recognizes a ‘cross’ category but automake does not, and automake recognizes ‘extra-portability’ and ‘portability-recursive’ categories but autoconf does not. This means that if you do ‘autoreconf -Wcross’ you will get warnings about an unknown warning category from automake and aclocal. Conversely, ‘autoreconf -Wextra-portability’ will produce warnings from autoreconf itself + multiple instances of autom4te (depending on how complicated your configure script is). This is not just cosmetic, because ‘-Werror,cross’ or ‘-Werror,extra-portability’ will promote the message to an error and aclocal/autom4te will exit unsuccessfully. (Order matters: ‘-Wcross,error’ will just issue a warning.) At least one redistributor of Autoconf has felt a need to patch autoreconf to avoid supplying -Wcross to automake (checking first whether ‘cross’ shows up in automake’s ‘--help’ output). Clearly ChannelDefs.pm should be brought back into sync between the two projects, but that will only fix the problem after *both* Autoconf and Automake do a release. So I’m wondering whether it would make sense to merge this distributor’s patch to avoid supplying -Wcross to automake -- perhaps generalized to arbitrary warning categories. What do you think? zw
