PKG Build -- Generate ChangeLog files during package build.

PKG Build -- Generate ChangeLog files during package build.

	* XEmacs.rules (CHANGELOG_XEMACS): New.  Set to 'ChangeLog.XEmacs'
	if that file exists in the package directory, unset otherwise.
	(ChangeLog): New target for generating the package's ChangeLog.
	(package-info): Make 'ChangeLog' a dependency.
	(clean): Also delete ChangeLog, it's a generated file now.
	(binkit-1): Install the ChangeLog.XEmacs file if it exists.

	* .gitignore: Package ChangeLogs are now generated.  Ignore them.

Signed-off-by: Steve Youngs <steve@sxemacs.org>