deprecated-configure-filename

[kartikm]

Reported by Debian's Lintian:

X: chmlib source: deprecated-configure-filename
N:
N: The use of 'configure.in' with automake is deprecated and will not be
N: supported in future versions of automake. Please consider (helping
N: upstream) migrating to 'configure.ac' instead.
N:
N: Refer to
N: https://lists.gnu.org/archive/html/automake/2013-05/msg00049.html for
N: details.
N:
N: Severity: wishlist, Certainty: certain
N:
N: Check: automake, Type: source

Thanks!