be sure this directory exist (lynx compile errror because of missing ncurses5-config)

mk/build.mk

@@ -136,7 +136,7 @@ ifeq ($(ADK_TARGET_PACKAGE_IPKG),y)
 endif
 
 ${STAGING_DIR} ${STAGING_DIR}/etc ${STAGING_HOST_DIR}:
-	mkdir -p ${STAGING_DIR}/{bin,etc,lib,usr/include,usr/lib/pkgconfig} \
+	mkdir -p ${STAGING_DIR}/{bin,etc,lib,usr/bin,usr/include,usr/lib/pkgconfig} \
 		${STAGING_HOST_DIR}/{bin,lib,usr/bin,usr/lib}
 
 ${STAGING_DIR}/etc/ipkg.conf: ${STAGING_DIR}/etc