sane-backends: install to staging

Other packages might depend on sane, thus it should install its
development files.

Signed-off-by: André Hentschel <nerv@dawncrow.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/sane-backends/sane-backends.mk

@@ -9,6 +9,7 @@ SANE_BACKENDS_SITE = http://sources.buildroot.net
 SANE_BACKENDS_CONFIG_SCRIPTS = sane-config
 SANE_BACKENDS_LICENSE = GPLv2+
 SANE_BACKENDS_LICENSE_FILES = COPYING
+SANE_BACKENDS_INSTALL_STAGING = YES
 
 ifeq ($(BR2_PACKAGE_LIBUSB),y)
 SANE_BACKENDS_DEPENDENCIES += libusb