Re: [PATCH 1/4] Document new hard requirement on GNU make

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 16 Nov 2016 12:05:02 -0500
> From: Simon Marchi <simon.marchi@polymtl.ca>
> Cc: Simon Marchi <simon.marchi@ericsson.com>, gdb-patches@sourceware.org
> 
> > Should we decide which oldest version of GNU Make we are willing to
> > support?  IOW, which features do we need for the build?
> > 
> > Thanks.
> 
> Probably, yes, but I'm not aware of the exact features/bugfix we have to 
> rely on.  From what I can see, pattern rules have been around since 
> forever (I checked out a commit of make from 1993, and it was already in 
> the doc).  However, if there is a particular bug about pattern rules in 
> some versions of make we want to avoid, I am not aware of it.

If all we want to use is pattern rules, then there's no problem.  But
I envision that soon enough we'd want to use more, like
target-specific variables, functions like $(eval) and $(file),
variables like $(MAKE_HOST), etc.

> %.o: %.c
>    <generic compilation commands>
> 
> %-ipa.o: %-ipa.c
>    <ipa-specific compilation commands>
> 
> With make >= 3.82, it would do the right thing (choose the second one), 
> by choosing the rule with the shorter stem.  Before that, it used the 
> order of definition (the first that matches wins).  So it would be nice 
> for that reason to require >= 3.82, but it's also possible to work 
> around if that's too recent.

3.82 shouldn't be a problem, I think.