Re: [PATCH] gnumakefile: better interaction with Automake-NG

[Stefano Lattarini]

On 08/02/2012 07:49 PM, Eric Blake wrote:
> On 08/02/2012 11:00 AM, Eric Blake wrote:
>> On 08/02/2012 10:53 AM, Stefano Lattarini wrote:
>>> * modules/gnumakefile [Makefile.am]: The makefiles generated by
>>> Automake-NG always contain a definition of VPATH, even in non-VPATH
>>> builds (its value being simply '.' in that case).  So, in the
>>> 'clean-GNUmakefile' rule, to determine whether running under a
>>> VPATH setup, compare '$(srcdir)' to '.' rather than checking whether
>>> '$(VPATH)' expands to the empty string.
>>> ---
>>
>> That fixes things with automake-ng, but what about with existing automake?
>>
The above copies an idiom mainline Automake emits in its own Makefiles
(when cleaning $(CONFIG_CLEAN_VPATH_FILES)) so I say we're safe :-)

>>>  clean-GNUmakefile:
>>> -   test x'$(VPATH)' != x && rm -f $(top_builddir)/GNUmakefile || :
>>> +   test '$(srcdir)' = . || rm -f $(top_builddir)/GNUmakefile
>>
>> That is, shouldn't this really be:
>>
>> case '$(srcdir)' in
>>   .|'') ;;
>>   *) rm -f $(top_builddir)/GNUmakefile ;;
>> esac
> 
> Or am I misreading things again?  I guess your complaint is that for
> in-tree builds, $(VPATH) has changed between empty and '.' depending on
> automake version, but that $(srcdir) has always been '.' for both
> settings of VPATH.
> 
Exactly.  Changing $(srcdir) in any way would cause major breakages
everywhere!

Regards,
  Stefano