Add m4/README and .gitignore.

.gitignore

@@ -0,0 +1,41 @@
+
+# Object code
+*.o
+*.so
+*.lo
+*.la
+
+# gcov files
+*.gcda
+*.gcov
+*.gcno
+
+# Backup files
+*~
+
+# Release files
+*.tar.gz
+
+# Files currently being edited by vim or vi
+*.swp
+
+# automake/autoconf
+.deps/
+.libs/
+Makefile
+Makefile.in
+aclocal.m4
+autom4te.cache/
+m4/*
+!README
+config.guess
+config.log
+config.status
+config.sub
+configure
+depcomp
+install-sh
+libtool
+ltmain.sh
+missing
+

m4/README

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+This file exists such that the m4/ directory will be created when cloning the
+git repository.
+
+The m4/ directory is not directly used by this project, but libtoolize
+populates this directory with files, recommending that the directory be
+included in the macro search path for aclocal.
+
+Because autoreconf runs aclocal before libtoolize, this directory will not
+exist when autoreconf is run, triggering an error from aclocal.
+
+Creating this directory (and keeping this file in it as a placeholder)
+prevents this error.