[xml] libxml configure script not GNU compliant

[Bob Friesenhahn <bfriesen simple dallas tx us>]

The configure script delivered with libxml does not support the
reqirements of the GNU coding standards.  Specifically, it does
not support reliably passing options to configure via standard
environment variables.

The following should serve to select the compiler:

  CC='gcc -m64' ./configure

but the configure script ignores this setting and uses plain gcc
instead.

The inability to control how libxml is compiled and linked has been a
constant thorn in my side so I have subscribed to the list just to
voice this compliaint.

Libxml uses a version of Autoconf (2.13) that dates back to 1996.
This makes the build environment more difficult to use and certainly
decreases portability.

Bob
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Bob Friesenhahn
bfriesen simple dallas tx us
http://www.simplesystems.org/users/bfriesen