attempt to change configuration files for detection for cups3

Makefile.am

@@ -44,12 +44,20 @@ config.py: config.py.in Makefile
 	  -e "s|\@PACKAGE\@|$(PACKAGE)|" \
 	  $< > $@
 
+if HAVE_CUPS_3
+CUPSCONF_SYSCONFDIR =
+CUPSCONF_SERVERBINDIR =
+else
+CUPSCONF_SYSCONFDIR = $(sysconfdir)
+CUPSCONF_SERVERBINDIR = $(cupsserverbindir)
+endif
+
 cupshelpers/config.py: cupshelpers/config.py.in Makefile
 	$(mkdir_p) cupshelpers
 	sed \
 	  -e "s|\@prefix\@|$(prefix)|" \
-	  -e "s|\@sysconfdir\@|$(sysconfdir)|" \
-	  -e "s|\@cupsserverbindir\@|$(cupsserverbindir)|" \
+	  -e "s|\@sysconfdir\@|$(CUPSCONF_SYSCONFDIR)|" \
+	  -e "s|\@cupsserverbindir\@|$(CUPSCONF_SERVERBINDIR)|" \
 	  $< > $@
 
 dbus/org.fedoraproject.Config.Printing.service: dbus/org.fedoraproject.Config.Printing.service.in $(top_builddir)/config.status Makefile
@@ -191,8 +199,8 @@ if UDEV_RULES
 udevrules_DATA=udev/70-printers.rules
 udev_udev_configure_printer_SOURCES=\
 	udev/udev-configure-printer.c
-udev_udev_configure_printer_LDADD= -lcups -ludev $(libusb_LIBS) $(GLIB_LIBS)
-udev_udev_configure_printer_CFLAGS= $(AM_CFLAGS) $(libusb_CFLAGS) $(GLIB_CFLAGS)
+udev_udev_configure_printer_LDADD= $(CUPS_LIBS) -ludev $(libusb_LIBS) $(GLIB_LIBS)
+udev_udev_configure_printer_CFLAGS= $(AM_CFLAGS) $(CUPS_CFLAGS) $(libusb_CFLAGS) $(GLIB_CFLAGS)
 udev_PROGRAMS=\
 	udev/udev-configure-printer
 udev_SCRIPTS=\

configure.ac

@@ -35,30 +35,56 @@ AC_SUBST(DESKTOPPREFIX)
 PKG_PROG_PKG_CONFIG
 
 dnl Allow manual definition for CUPS SERVERBIN, if not defined, use value from pkg-config...
+dnl For CUPS 3 (cups3.pc / libcups3), this is not required and may be left empty.
 AC_MSG_CHECKING([for CUPS SERVERBIN dir])
 AC_ARG_WITH([cups_serverbin_dir],
   AS_HELP_STRING([--with-cups-serverbin-dir], [set CUPS SERVERBIN dir, default=value from pkg-config]), [
     cupsserverbindir="$withval"
     AC_MSG_RESULT([$withval])
   ], [
     AS_IF([test "x$PKG_CONFIG" != x], [
-      AS_IF([$PKG_CONFIG --exists cups], [
-          cupsserverbindir=$($PKG_CONFIG --variable=cups_serverbin cups)
-          AC_MSG_RESULT([$cupsserverbindir])
+      dnl First try CUPS 3 (cups3.pc). CUPS 3 does not need serverbin, so we
+      dnl simply allow an empty value here.
+      AS_IF([$PKG_CONFIG --exists cups3], [
+          cupsserverbindir=""
+          AC_MSG_RESULT([none (CUPS 3)])
         ], [
-          AC_MSG_ERROR([No CUPS pkgconfig file present and no CUPS SERVERBIN dir defined in configure options.])
+          dnl Fall back to CUPS 2 (cups.pc) which still defines cups_serverbin.
+          AS_IF([$PKG_CONFIG --exists cups], [
+              cupsserverbindir=$($PKG_CONFIG --variable=cups_serverbin cups)
+              AC_MSG_RESULT([$cupsserverbindir])
+            ], [
+              AC_MSG_ERROR([No CUPS pkgconfig file present (cups3.pc or cups.pc) and no CUPS SERVERBIN dir defined in configure options.])
+            ])
         ])
     ], [
       AC_MSG_ERROR([No pkg-config present and no CUPS SERVERBIN dir defined in configure options.])
     ])
 ])
 
-AS_IF([test "x$cupsserverbindir" = x], [
-  AC_MSG_ERROR([No CUPS SERVERBIN dir defined in CUPS pkgconfig file or configure options.])
-])
-
 AC_SUBST(cupsserverbindir)
 
+dnl Check for CUPS library (CUPS 3 via cups3.pc, else CUPS 2 via cups.pc)
+AC_MSG_CHECKING([for CUPS library])
+
+PKG_CHECK_MODULES([CUPS], [cups3], [
+    have_cups3=yes
+    AC_DEFINE([HAVE_CUPS_3], [1], [Define if CUPS 3.x (libcups3) is available])
+    cups_version=`$PKG_CONFIG --modversion cups3`
+  ], [
+    have_cups3=no
+    PKG_CHECK_MODULES([CUPS], [cups >= 1.6], [
+        cups_version=`$PKG_CONFIG --modversion cups`
+      ], [
+        AC_MSG_ERROR([CUPS library not found. Need cups3.pc or cups.pc >= 1.6])
+      ])
+  ])
+
+AC_MSG_RESULT([$cups_version])
+AC_SUBST([CUPS_CFLAGS])
+AC_SUBST([CUPS_LIBS])
+AM_CONDITIONAL([HAVE_CUPS_3], [test "x$have_cups3" = "xyes"])
+
 PKG_CHECK_MODULES(GLIB, glib-2.0, has_glib=yes, has_glib=no)
 
 AC_ARG_WITH(udev-rules,