bison: fix random build failure

component/bison/buildout.cfg

 [buildout]
 extends =
-  ../autoconf/buildout.cfg
-  ../automake/buildout.cfg
   ../m4/buildout.cfg
   ../patch/buildout.cfg
   ../perl/buildout.cfg
@@ -16,7 +14,15 @@ url = https://ftp.gnu.org/gnu/bison/bison-3.8.2.tar.xz
 md5sum = c28f119f405a2304ff0a7ccdcc629713
 environment =
   M4=${m4:location}/bin/m4
-  PATH=${autoconf:location}/bin:${automake:location}/bin:${patch:location}/bin:${perl:location}/bin:${xz-utils:location}/bin:%(PATH)s
+  PATH=${patch:location}/bin:${perl:location}/bin:${xz-utils:location}/bin:%(PATH)s
 patch-options = -p1
 patches =
   ${:_profile_base_location_}/01_inhibit_example_generation#ee2df22601a56d738939fa760f9dc19b
+# Make sure that Makefile.in is not older that the other file that is modified
+# by the above patch, otherwise `make` would invoke automake, which is likely
+# to fail with an error like:
+#   This is Automake 1.16.5, but the definition used by this AM_INIT_AUTOMAKE
+#   comes from Automake 1.16.4.
+# Without such pre-configure, the 2 files usually have the same modification
+# date because machines are fast, but not always.
+pre-configure = touch Makefile.in