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 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,HOST} 
macros 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, but if it 
is agreed that it is, I'll file this report and offer a patch.

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