TTY + General build chain related updates

* merges:
  Conditional automake init
  Small configure.ac fix
  Fix info/Makefile.am for old automake
  Allow m4 and autostuff to be customized
  Enforce makeinfo version
  Improve TTY library detection
  Improve TTY section of summary
  Add builtin tty support option
  Forward compatible info in builddir (when CLEANFILES becomes obsolete)
  Attempt to provide speed_t
  Improve term initialization output
  Provide helper defines
  Allow for ncurses tinfo as TTY option