[clutter-gst/clutter-gst-3.0] Make libgudev dependency controllable by configure switch

[Lionel Landwerlin <llandwerlin src gnome org>]

commit 9d523d05f26ed323dadf5f8e3695d35e95dad9ff
Author: Gilles Dartiguelongue <eva gentoo org>
Date:   Tue Nov 24 11:32:37 2015 +0100

    Make libgudev dependency controllable by configure switch

 configure.ac |   31 ++++++++++++++++++++++++-------
 1 files changed, 24 insertions(+), 7 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 67dede9..6e76a38 100644
--- a/configure.ac
+++ b/configure.ac
@@ -209,13 +209,30 @@ AS_IF([test "x$have_cogl_osx" = xyes],
         AC_SUBST([GL_LDFLAGS])
       ])
 
-PKG_CHECK_MODULES(GUDEV,
-                 [gudev-1.0],
-                 [
-                   have_gudev=yes
-                   AC_DEFINE([HAVE_GUDEV], [1],
-                             ["Defined if gudev is available"])
-                 ],[ have_gudev=no ])
+m4_define([udev_default], auto)
+AC_ARG_ENABLE([udev],
+              [AS_HELP_STRING([--enable-udev],
+                              [Enable camera listing through libgudev @<:@default=]udev_default[@:>@])],
+              [],
+              [enable_udev=udev_default])
+
+AS_IF([test "$enable_udev" != "no"],
+      [
+        PKG_CHECK_MODULES(GUDEV,
+                          [gudev-1.0],
+                          [
+                            have_gudev=yes
+                            AC_DEFINE([HAVE_GUDEV], [1],
+                                      ["Defined if gudev is available"])
+                          ],[
+                            AS_IF([test "$with_udev" = "yes"],
+                                  [AC_MSG_ERROR([Could not find libgudev])],
+                                  [have_gudev=no])
+                          ])
+      ],
+      [
+        have_gudev=no
+      ])
 
 dnl ========================================================================
 dnl Experimental support for hardware accelerated decoders.