Re: unesthetic build commands generated by automake

[Alexandre Duret-Lutz]

>>> "Bruno" == Bruno Haible <address@hidden> writes:

[...]

 Bruno> The issue being VPATH support for non-GNU makes, my summary is that
 Bruno> they don't support VPATH well:

 Bruno> 1) GNU make supports VPATH with both .c.o and %.o:%.c rules.

 Bruno> 2) Solaris make should not be used with VPATH at all, as it randomly
 Bruno> changes Makefile variables.

 Bruno> 3) FreeBSD make does not support %.o:%.c rules at all. For the
 Bruno> remaining .c.o rules VPATH is taken into account. For
 Bruno> additional dependencies like "foo.o : bar.c" it is not.

FWIW, Automake doesn't support %-rule.  This is not portable,
not POSIX, nothing.  You can run `automake -Wportability' to get
warning about these (BTW, these warnings are likely to be turned
on by default in 1.8 -- people who know what they do can start
using `AUTOMAKE_OPTIONS = -Wno-portability' now).

About VPATH builds, Solaris make should work (I have yet to
update the `Limitations of Make' section of the Autoconf manual
to explain how Automake copes with this).

BSD make used to work too, but apparently they recently changed
it so that it no longer performs VPATH search for dependencies
which are target.  That means parser.c will always be rebuilt
from parser.y during a VPATH build, even if $(srcdir)/parser.c
exists :(
-- 
Alexandre Duret-Lutz