package/libv4l: add optional support for libglu

libv4l has optional support for libglu:
https://git.linuxtv.org/v4l-utils.git/tree/configure.ac#n166

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/libv4l/libv4l.mk

@@ -47,6 +47,10 @@ else
 LIBV4L_CONF_OPTS += --without-libudev
 endif
 
+ifeq ($(BR2_PACKAGE_LIBGLU),y)
+LIBV4L_DEPENDENCIES += libglu
+endif
+
 ifeq ($(BR2_PACKAGE_LIBV4L_UTILS),y)
 LIBV4L_CONF_OPTS += --enable-v4l-utils
 # clock_gettime is used, which is provided by librt for glibc < 2.17