[gegl] add autoconf check for libv4l2

[Øyvind Kolås <ok src gnome org>]

commit 69e4a0960e2fe0067e4f6ef1330fdc4ed3e88c5f
Author: nick black <nick black sprezzatech com>
Date:   Fri Dec 14 00:30:44 2012 -0500

    add autoconf check for libv4l2

 configure.ac                            |   12 +++++++++++-
 operations/external/v4lutils/v4lutils.h |    1 -
 2 files changed, 11 insertions(+), 2 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index c496838..ef78310 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1055,7 +1055,17 @@ AC_ARG_WITH(libv4l, [  --without-libv4l        build without V4L support])
 
 have_v4l="no"
 if test "x$with_libv4l" != "xno"; then
-  AC_CHECK_HEADER(linux/videodev2.h, have_v4l="yes")
+  AC_CHECK_HEADER(linux/videodev2.h,
+    [have_v4l="yes"],
+    [have_v4l="no (kernel header not found)"])
+  else
+    have_v4l="no  (disabled with --without-libv4l)"
+fi
+
+if test "x$have_v4l" = "xyes"; then
+  PKG_CHECK_MODULES(V4l, libv4l2,
+    [have_v4l="yes"],
+    [have_v4l="no   (v4l library not found)"])
 fi
 
 AM_CONDITIONAL(HAVE_V4L, test "$have_v4l" = "yes")
diff --git a/operations/external/v4lutils/v4lutils.h b/operations/external/v4lutils/v4lutils.h
index eee9bc1..be432db 100644
--- a/operations/external/v4lutils/v4lutils.h
+++ b/operations/external/v4lutils/v4lutils.h
@@ -51,7 +51,6 @@ struct _v4ldevice
        struct video_buffer buffer;
        struct video_mmap mmap;
        struct video_mbuf mbuf;
-       // struct video_unit unit;
        unsigned char *map;
        pthread_mutex_t mutex;
        int frame;