* automake.in (am_macro_for_var, ac_macro_for_var,

* automake.in (am_macro_for_var, ac_macro_for_var,
required_variables): New variables.
(am_c_prototypes, seen_prog_lex, am_lispdir_location,
pythondir_location): Remove.
(initialize_per_input): Clear %required_variables.
(require_variables, require_variables_for_macro): New functions.
(handle_languages): Call &require_variables for $lang->config_vars.
(handle_compile): Call &require_variables_for_macro for the
ANSI2KNR and U variables.
(handle_emacs_lisp): Call &require_variables for EMACS and libdir.
(handle_python): Call &require_variables for PYTHON.  Don't
explicitly allow `python' as a prefix for PYTHON.
(scan_autoconf_traces): Don't scan AC_PROG_LEX, AM_C_PROTOTYPES,
AM_PATH_LISPDIR, and AM_PATH_PYTHON.
(scan_autoconf_traces) <AC_SUBST>: Don't filter out ANSI2KNR and
AMDEPBACKSLASH here...
(define_configure_variable): ... do this here.
(am_primary_prefixes): Probe the existence of ${X}dir using
&require_variables_for_macro.  If a standard prefix is not
legitimate, say so.  Ignore all configure variables.
* tests/ansi8.test, tests/cxx2.test, tests/gcj5.test,
tests/lisp2.test, tests/python2.test: New files
* tests/Makefile.am (TESTS): Add them.
* tests/asm.test: Grep stderr.
* tests/lex2.test: Rewrite to test that Automake suggests AM_PROG_LEX.
* tests/python.test: Make sure py-compile is installed.