autoconf: use AC_PROG_YACC/LEX

Needed for automake. Using AC_PROG_PATH(bison/flex) causes automake to
fail to build .y and .l files.

It is up to the builder to use bison/flex instead of yacc/lex.

Reviewed-by: Eric Anholt <eric@anholt.net>
Tested-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Matt Turner <mattst88@gmail.com>
3 files changed