Bugfix: "make distcheck" failed some reasons .

* Bugfix: "make distcheck" failed .
** remove "msg" directory .
"msg" dir was not used .
** modify man/Makefile.am .
pow.1 is generated automatically .
But I forgot remove make clean .
Then I modified man/Makefile.am .
** modify each Makefile.am
Changed from "-I$(top_builddir)" to "-I$(top_srcdir)" .

* Change autoconf version 2.69 -> 2.68 .

	modified:   INSTALL
	modified:   Makefile.am
	modified:   Makefile.in
	modified:   aclocal.m4
	modified:   autom4te.cache/output.0
	modified:   autom4te.cache/output.1
	modified:   autom4te.cache/requests
	modified:   autom4te.cache/traces.0
	modified:   autom4te.cache/traces.1
	modified:   config.guess
	modified:   config.sub
	modified:   configure
	modified:   configure.ac
	modified:   configure.scan
	modified:   depcomp
	modified:   include/Makefile.in
	modified:   install-sh
	modified:   libpow/Makefile.am
	modified:   libpow/Makefile.in
	modified:   man/Makefile.am
	modified:   man/Makefile.in
	modified:   man/ja/Makefile.in
	deleted:    man/pow.1
	modified:   missing
	deleted:    msg/Makefile.am
	deleted:    msg/ja.cat
	deleted:    msg/ja.msg
	modified:   pow/Makefile.am
?	renamed:    msg/Makefile.in -> pow/Makefile.in
	deleted:    test-driver
	modified:   tests/Makefile.am
	modified:   tests/Makefile.in