Add use_v4lplugin flag to enable v4l2 library

third_party/v4l-utils/lib/include/libv4l1.h

Index: third_party/v4l-utils/lib/include/libv4l1.h
diff --git a/third_party/v4l-utils/lib/include/libv4l1.h b/third_party/v4l-utils/lib/include/libv4l1.h
new file mode 100644
index 0000000000000000000000000000000000000000..e16dea1c0f6053ece746921ac8dbe633fd58a869
--- /dev/null
+++ b/third_party/v4l-utils/lib/include/libv4l1.h
@@ -0,0 +1,75 @@
+/*
+#             (C) 2008 Hans de Goede <hdegoede@redhat.com>
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation; either version 2.1 of the License, 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 Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA  02110-1335  USA
+*/
+
+#ifndef __LIBV4L1_H
+#define __LIBV4L1_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <libv4l1-videodev.h>
+
+#if HAVE_VISIBILITY
+#define LIBV4L_PUBLIC __attribute__ ((visibility("default")))
+#else
+#define LIBV4L_PUBLIC
+#endif
+
+/* Point this to a FILE opened for writing when you want to log error and
+   status messages to a file, when NULL errors will get send to stderr */
+LIBV4L_PUBLIC extern FILE *v4l1_log_file;
+
+/* Just like your regular open/close/etc, except that when opening a v4l2
+   capture only device, full v4l1 emulation is done including emulating the
+   often not implemented in v4l2 drivers CGMBUF ioctl and v4l1 style mmap call
+   in userspace.
+
+   Format conversion is done if necessary when capturing. That is if you
+   (try to) set a capture format which is not supported by the cam, but is
+   supported by libv4lconvert then SPICT will succeed and on SYNC / read the
+   data will be converted for you and returned in the request format.
+
+   Note that currently libv4l1 depends on the kernel v4l1 compatibility layer
+   for: 1) Devices which are not capture only, 2) Emulation of many basic
+   v4l1 ioctl's which require no driver specific handling.
+
+   Note that no functionality is added to v4l1 devices, so if for example an
+   obscure v4l1 device is opened which only supports some weird capture format
+   then libv4l1 will not be of any help (in this case it would be best to get
+   the driver converted to v4l2, as v4l2 has been designed to include weird
+   capture formats, like hw specific bayer compression methods).
+*/
+
+LIBV4L_PUBLIC int v4l1_open(const char *file, int oflag, ...);
+LIBV4L_PUBLIC int v4l1_close(int fd);
+LIBV4L_PUBLIC int v4l1_dup(int fd);
+LIBV4L_PUBLIC int v4l1_ioctl(int fd, unsigned long int request, ...);
+LIBV4L_PUBLIC ssize_t v4l1_read(int fd, void *buffer, size_t n);
+LIBV4L_PUBLIC void *v4l1_mmap(void *start, size_t length, int prot, int flags,
+		int fd, int64_t offset);
+LIBV4L_PUBLIC int v4l1_munmap(void *_start, size_t length);
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#endif