ssh/Makefile.am [HAVE_GUILE_VM]: Compile Guile modules.

* configure.ac: Add check for Guile VM's compiler.
  (AC_CONFIG_FILES): Add `am/Makefile'.
* Makefile.am (SUBDIRS): Add `am' directory.
* ssh/Makefile.am [HAVE_GUILE_VM]: Compile Guile modules and
  install produced *.go files.
* am/guilec: New file.
* am/snarf (AM_V_SNARF_0): Improve formatting.
* ssh/.gitignore: New file.
* NEWS: Update.