Automake needs to recognise AC_CANONICAL_BUILD

[Norman Gray]

Greetings,

In the current autoconf (which I'm taking to be 2.59), the canonical 
system type is determined through a trinity of 
AC_CANONICAL_{BUILD,HOST,TARGET}, the first of which is defaulted by 
config.guess, which therefore needs to be installed if 
AC_CANONICAL_BUILD is spotted.  This is different from autoconf 2.13 
(for example), which had just AC_CANONICAL_{SYSTEM,HOST}.

Automake 1.9 (in scan_autoconf_traces) still tests for only the 
{SYSTEM,HOST} macros, and so fails to install config.guess if 
AC_CANONICAL_BUILD is present.

I believe this is an error, and config.guess should be installed if any 
of {BUILD,HOST,TARGET} is present (since each defaults to the previous 
one).  Presumably the support for the autoconf-deprecated SYSTEM macro 
should be retained but not advertised.

I haven't filed this as a bug report, because I'm never _absolutely_ 
convinced I understand the {BUILD,HOST,TARGET} distinction (I did mail 
bug-automake earlier today, but the message hasn't yet appeared).  In 
case it is indeed a bug, I've attached a patch which makes automake 
support all four AC_CANONICAL_(BUILD|HOST|SYSTEM|TARGET).  This is a 
patch against distributed 1.9.

I haven't yet completed FSF copyright paperwork, though I'm in the 
process or organising that for other patches I hope to contribute.  
Perhaps this patch is too small to require paperwork.

All the best,

Norman


--
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Norman Gray  :  Physics & Astronomy, Glasgow University, UK
http://www.astro.gla.ac.uk/users/norman/  :  www.starlink.ac.uk

automake-1.9-patch
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