Hello automakers. A small update on this ...
On Saturday 22 January 2011, Ralf Wildenhues wrote: > * Stefano Lattarini wrote on Fri, Jan 21, 2011 at 10:28:24PM CET: > > - Always create yacc-derived and distributed .c and .h files in > > $(srcdir), and explicitly instruct make to alwsys look fr them > > there at first -- similarly to what is done for info files > > (yuck) > > Yes, this is ugly, but it is a way that can be made to work. > One complication is that, for portable semantics, if a file is > ever mentioned as $(srcdir)/file as a prerequisite, then it also > needs to be listed that way as a target. (I think; it might've > been the other way round.) > > Downside of this is that now builds fail to work as expected when > there are newer versions of the files in the build tree. GNU make > users would likely complain. > Yes... and they would be right IMO. To be honest, if I were just an automake user, I'd complain myself about such a behaviour. So IMVHO this is not a viable solution, after all. > Still, this could be viable as optional behavior. > > > - Tell the developer to add proper AC_CONFIG_LINKS to configure in > > order to support VPATH builds with FreeBSD make (yuck^2, since > > that means keeping track of renamed files when object-specific > > flags are involved). > > Hmm... maybe a variation of this might be a good solution after all, at least for FreeBSD make: the special `.BEGIN' target[1][2] might be used to copy Yacc-derived *.c and *.h files from $(srcdir) to $(builddir), unless they are already there. [1] See <http://www.freebsd.org/cgi/man.cgi?query=make> for more info. [2] This variable doesn't seem to cause problems with GNU make, Solaris XPG4/CCS make, Solaris dmake, not Heirloom make. Note that the 'distcleancheck' target would still fail with this change, but that's more of an annoyance rather than a serious bug (like the one under discussion is IMHO). And we could try to fix that later. > > - Make the `parse.c' and `parse.h' rules look for same named files > > in $(srcdir) during a VPATH build, and copy them in $(builddir) > > if they're neweer than `parse.y'. But then how can distclean be > > made to work in evey situation? > > I doubt that these two options can be made to work sanely. A > file: $(srcdir)/file > > doesn't work with GNU make, for example: it will rightfully complain > about a circular dependency. > > > - Tell that FreeBSD make is not supported in VPATH builds (not > > really a solution, I admit). > > Why not? VPATH is not specified by Posix, and there is a reason for > that: behavior is just too variable and different between makes. This > means that only some setups work well, others don't. > > I'm concerned mostly with users downloading stuff: they should be able > to build source packages. If VPATH doesn't work, that is not a big > problem because they can still use an in-tree build. It doesn't make > the package unusable for them. > Anyway, I think this bug woul be worth fixing, if that can be done without too much fuss. > The actual complication, as far as I can see, comes from the fact that > I want VPATH builds to work for the packages I'm interested in. ;-) > :-) Regards, Stefano
