* automake.in (scan_one_autoconf_file): Declare

* automake.in (scan_one_autoconf_file): Declare
LEX_OUTPUT_ROOT and LEXLIB as configure variables when
AM_PROG_LEX or AC_PROG_LEX are seen.  This allows to ...
* lib/am/lex.am: ... remove the LEX_OUTPUT_ROOT and LEXLIB
definitions.  Search %SOURCE% in $(srcdir).  Use s||| instead
of s/// in the sed invocation, to support filenames containing
slashes.
* lib/am/yacc.am: Search %SOURCE% in $(srcdir).  Use s||| too.
* tests/lex5.test, tests/yacc8.test: New files.
* tests/Makefile.am (TESTS): Add them.