Add a --disable-maintainer-mode option to configure.

acinclude.m4

@@ -0,0 +1,36 @@
+# Add --enable-maintainer-mode option to configure.
+# From Jim Meyering
+# Change it to enable maintainer mode by default by Nicolas Boullis.
+
+# Copyright 1996, 1998, 2000, 2001, 2002  Free Software Foundation, Inc.
+# Copyright 2004  Nicolas Boullis.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2, or (at your option)
+# any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
+# 02111-1307, USA.
+
+AC_DEFUN([AM_MAINTAINER_MODE],
+[AC_MSG_CHECKING([whether to enable maintainer-specific portions of Makefiles])
+  dnl maintainer-mode is enabled by default
+  AC_ARG_ENABLE(maintainer-mode,
+[  --disable-maintainer-mode disable make rules and dependencies not useful
+                          (and sometimes confusing) to the casual installer],
+      USE_MAINTAINER_MODE=$enableval,
+      USE_MAINTAINER_MODE=yes)
+  AC_MSG_RESULT([$USE_MAINTAINER_MODE])
+  AM_CONDITIONAL(MAINTAINER_MODE, [test $USE_MAINTAINER_MODE = yes])
+  MAINT=$MAINTAINER_MODE_TRUE
+  AC_SUBST(MAINT)dnl
+]
+)

configure.in

@@ -2,6 +2,8 @@ AC_INIT(src/isync.h)
 AM_CONFIG_HEADER(config.h)
 AM_INIT_AUTOMAKE(isync, 0.9.2)
 
+AM_MAINTAINER_MODE
+
 AM_PROG_CC_STDC
 if test "$GCC" = yes; then
     CFLAGS="$CFLAGS -pipe -W -Wall -Wshadow -Wmissing-prototypes"