config: comment, minor upgrade, quote and layout configure.ac

Group statements per section as per Autoconf standard layout
Quote statements where appropriate.
Autoconf recommends not using dnl instead of # for comments

Use AC_CONFIG_FILES to replace the deprecated AC_OUTPUT with parameters.
Add AC_CONFIG_SRCDIR([Makefile.am])

This helps automated maintenance and release activities.
Details can be found in http://wiki.x.org/wiki/NewModuleGuidelines

configure.ac

-dnl 
-dnl  Copyright © 2003 Keith Packard, Noah Levitt
-dnl 
-dnl  Permission to use, copy, modify, distribute, and sell this software and its
-dnl  documentation for any purpose is hereby granted without fee, provided that
-dnl  the above copyright notice appear in all copies and that both that
-dnl  copyright notice and this permission notice appear in supporting
-dnl  documentation, and that the name of Keith Packard not be used in
-dnl  advertising or publicity pertaining to distribution of the software without
-dnl  specific, written prior permission.  Keith Packard makes no
-dnl  representations about the suitability of this software for any purpose.  It
-dnl  is provided "as is" without express or implied warranty.
-dnl 
-dnl  KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
-dnl  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
-dnl  EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
-dnl  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
-dnl  DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
-dnl  TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
-dnl  PERFORMANCE OF THIS SOFTWARE.
-dnl
-dnl Process this file with autoconf to create configure.
+#
+#  Copyright © 2003 Keith Packard, Noah Levitt
+#
+#  Permission to use, copy, modify, distribute, and sell this software and its
+#  documentation for any purpose is hereby granted without fee, provided that
+#  the above copyright notice appear in all copies and that both that
+#  copyright notice and this permission notice appear in supporting
+#  documentation, and that the name of Keith Packard not be used in
+#  advertising or publicity pertaining to distribution of the software without
+#  specific, written prior permission.  Keith Packard makes no
+#  representations about the suitability of this software for any purpose.  It
+#  is provided "as is" without express or implied warranty.
+#
+#  KEITH PACKARD DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+#  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+#  EVENT SHALL KEITH PACKARD BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+#  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+#  DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+#  TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+#  PERFORMANCE OF THIS SOFTWARE.
+#
 
+# Initialize Autoconf
 AC_PREREQ([2.60])
+#
+# Version should match the current XComposite version. XCompositeQueryVersion
+# returns the version from xcompositewire.h, NOT the version we set here.
+# But we try to keep these the same.  Note that the library has an extra
+# digit in the version number to track changes which don't affect the
+# protocol, so Xcomposite version l.n.m corresponds to protocol version l.n
+# that 'revision' number appears in Xcomposite.h and has to be manually
+# synchronized.
+#
+AC_INIT(libXcomposite, [0.4.3],
+	[https://bugs.freedesktop.org/enter_bug.cgi?product=xorg], [libXcomposite])
+AC_CONFIG_SRCDIR([Makefile.am])
+AC_CONFIG_HEADERS([config.h])
 
-dnl
-dnl Version should match the current XComposite version. XCompositeQueryVersion
-dnl returns the version from xcompositewire.h, NOT the version we set here.
-dnl But we try to keep these the same.  Note that the library has an extra
-dnl digit in the version number to track changes which don't affect the
-dnl protocol, so Xcomposite version l.n.m corresponds to protocol version l.n
-dnl that 'revision' number appears in Xcomposite.h and has to be manually
-dnl synchronized.
-dnl
-AC_INIT(libXcomposite,
-	[0.4.3],
-	[https://bugs.freedesktop.org/enter_bug.cgi?product=xorg],
-	libXcomposite)
+# Initialize Automake
 AM_INIT_AUTOMAKE([foreign dist-bzip2])
 AM_MAINTAINER_MODE
 
+# Initialize libtool
+AC_PROG_LIBTOOL
+
 # Require X.Org macros 1.8 or later for MAN_SUBSTS set by XORG_MANPAGE_SECTIONS
 m4_ifndef([XORG_MACROS_VERSION],
 	  [m4_fatal([must install xorg-macros 1.8 or later before running autoconf/autogen])])
 XORG_MACROS_VERSION(1.8)
-AC_CONFIG_HEADERS(config.h)
-
-# Check for progs
-AC_PROG_LIBTOOL
-
 XORG_DEFAULT_OPTIONS
 XORG_WITH_XMLTO(0.0.20)
 
@@ -58,17 +57,18 @@ AM_CONDITIONAL([INSTALL_MANPAGES],
 
 # Check compositeext configuration, strip extra digits from package version to
 # find the required protocol version
-
 if test "$VERSION" = "" ; then
        VERSION=$PACKAGE_VERSION;
 fi
 COMPOSITEEXT_VERSION=[`echo $VERSION | sed 's/^\([0-9][0-9]*\.[0-9][0-9]*\).*$/\1/'`]
 AC_SUBST(COMPOSITEEXT_VERSION)
+
+# Obtain compiler/linker options for depedencies
 PKG_CHECK_MODULES(XCOMPOSITE, [compositeproto >= $COMPOSITEEXT_VERSION] x11)
 PKG_CHECK_MODULES(XFIXES, xfixes)
 
-AC_OUTPUT([Makefile
-	   src/Makefile
-	   man/Makefile
-           xcomposite.pc])
-
+AC_CONFIG_FILES([Makefile
+		src/Makefile
+		man/Makefile
+		xcomposite.pc])
+AC_OUTPUT