Re: [libvirt] [PATCH] build: Fix build with old automake
On Tue, Mar 18, 2014 at 06:27:48 -0600, Eric Blake wrote:
On 03/18/2014 05:00 AM, Jiri Denemark wrote:
>> Why don't we just avoid the whole issue by removing use of abs_srcdir
>> and abs_builddir. Can this rule:
>>
>> $(abs_builddir)/cpu/cpu_map.xml:
>> $(AM_V_GEN)ln -s $(abs_srcdir)/cpu/cpu_map.xml $@
>>
>> be just changed to
>>
>> cpu/cpu_map.xml:
>> $(AM_V_GEN)ln -s $(srcdir)/cpu/cpu_map.xml $@
>
> That's what I tried first but it does not work at all. I don't
> understand why but make thinks cpu/cpu_map.xml target is uptodate even
> though the file does not exist in builddir.
That would be VPATH rewriting at play. Does $(builddir)/cpu/cpu_map.xml
fare any better?
No, that doesn't work either.
...
But maybe that's some food for thought - instead of having a rule
that
uses a direct file name, perhaps you can instead have a witness rule on
a stamp file name, where we write the link ourselves when needed, and
then have all dependencies be on the stamp (which will ALWAYS exist only
in builddir):
cpu/cpu_map.xml.stamp:
$(AM_V_GEN)if test -f cpu/cpu_map.xml; then \
:; else \
ln -s `cd $(srcdir) && pwd`/cpu/cpu_map.xml \
cpu/cpu_map.xml; \
fi && touch $@
OK, this seems to work. It's uglier and doesn't regenerate the link if
someone removes it (the *.stamp file would need to be removed too) but
if that's considered a better way compared to setting abs_*dir, I can
make a proper patch out of it after testing it in all situations.
Jirka