bison: add automake as build dependency

Building Bison 3.3.2 now requires automake.

component/bison/buildout.cfg

 [buildout]
 extends =
+  ../automake/buildout.cfg
   ../m4/buildout.cfg
   ../perl/buildout.cfg
   ../xz-utils/buildout.cfg
@@ -12,6 +13,7 @@ shared = true
 url = http://ftp.gnu.org/gnu/bison/bison-3.3.2.tar.xz
 md5sum = c9b552dee234b2f6b66e56b27e5234c9
 environment =
+  AUTOMAKE=${automake:location}/bin/automake
   M4=${m4:location}/bin/m4
   PATH=${perl:location}/bin:${xz-utils:location}/bin:%(PATH)s
 patch-options = -p1