Update copyright dates, remove subversion $id strings, update .gitignore.

Depending on files generated during build via $(srcdir) breaks builds
that take place outside the source directory. This commit fixes one such
mistake in scripts/Makefile.am that refers to $(srcdir)/xdt-autogen.in.

Similar to AC_PROG_LIBTOOL, which has been replaced with LT_PREREQ
and LT_INIT, AC_PROG_INTLTOOL has been replaced with IT_PROG_INTLTOOL.
This commit makes xdt-autogen recommend intltool >= 0.35.0 and displays
a warning if AC_PROG_INTLTOOL is still being used in a configure script
template.

Original patch by Samuli Suominen <ssuominen@gentoo.org>

This gives warnings with full debug builds on recent gcc versions.

This disables the g_return_ macros, and quite often
we rely on that. So for the sake of stability, disable
those.

Use AUTOCONF_VERSION for automake-$ver, ACLOCAL_VERSION for
aclocal-$ver, AUTOMAKE_VERSION for automake-$ver and
AUTOHEADER_VERSION for autoheader-$ver.

This removes the custom checks for the //newest// binary
version, which gets constantly outdated.

Support LT_PREREQ as the new alternative of AC_PROG_LIBTOOL. If
the latter is used, show a message with information how to switch
to LT_PREREQ.

Mike Massonnet authored 13 years ago and Nick Schermer committed 13 years ago

The translations have been removed from the code -- Nick.

Use the macro shipped with pkg-config for detection of
$PKG_CONFIG. This to fix cross-build compatibility.

signal.h has an inline that redeclares __errno.

This breaks the sun studio compiler and since -g defaults
to level 2, it provides enough backtrace information.

The FreeBSD bot has some problems with this flag. Disable
it on non-linux systems, since it's not that important.