These files are used by a program called aclocal (part of the GNU automake
package).  aclocal uses these files to create aclocal.m4 which is in turn
used by autoconf to create the configure script at the the top level in
this distribution.

Some of these files are copies of the ones in the automake-1.1l
distribution.  Others are specific to this package.
Eventually, I expect that aclocal will evolve so that this directory
can contain only the .m4 files specific to this package.