automake: depends on autoconf, so select it

package/automake/Config.in

@@ -1,5 +1,6 @@
 config BR2_PACKAGE_AUTOMAKE
 	bool "automake"
+	select BR2_PACKAGE_AUTOCONF
 	help
 	  Tool for automatically generating Makefile's for input to
 	  configure scripts (made by autoconf).