Changed tiff-4.0.2 to demand autoconf 2.63 or later (which is common) rather

than 2.64 (which is currently a lot less common). This change seems to have
no negative effect, but allows builds to succeed on things like Centos.

libs/tiff-4.0.2/configure.ac

@@ -24,7 +24,7 @@ dnl OF THIS SOFTWARE.
 
 dnl Process this file with autoconf to produce a configure script.
 
-AC_PREREQ(2.64)
+AC_PREREQ(2.63)
 AC_INIT([LibTIFF Software],[4.0.2],[tiff@lists.maptools.org],[tiff])
 AC_CONFIG_AUX_DIR(config)
 AC_CONFIG_MACRO_DIR(m4)