configure.ac (in the AC_PREREQ command).
automake - at least the version specified near the start of
configure.ac (in the AM_INIT_AUTOMAKE command).
+git - at least Git 1.7.1. If your repository was created by an older
+ Git version, you may need to reclone it.
makeinfo - not strictly necessary, but highly recommended, so that
you can build the manuals.