doxygen: add explicit dependencies for host variant

Signed-off-by: Julien Floret <julien.floret@6wind.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>

package/doxygen/doxygen.mk

@@ -9,7 +9,7 @@ DOXYGEN_SOURCE = doxygen-$(DOXYGEN_VERSION).src.tar.gz
 DOXYGEN_SITE = http://ftp.stack.nl/pub/users/dimitri
 DOXYGEN_LICENSE = GPLv2
 DOXYGEN_LICENSE_FILES = LICENSE
-DOXYGEN_DEPENDENCIES = host-flex host-bison
+HOST_DOXYGEN_DEPENDENCIES = host-flex host-bison
 
 define HOST_DOXYGEN_CONFIGURE_CMDS
 	(cd $(@D); $(HOST_MAKE_ENV) ./configure --shared --prefix=$(HOST_DIR)/usr)