Offer suggestions for misspelled --param names.

Offer suggestions for misspelled --param names.

gcc/ChangeLog:
	* opts.c (handle_param): Use find_param_fuzzy to offer suggestions
	for misspelled param names.
	* params.c: Include spellcheck.h.
	(find_param_fuzzy): New function.
	* params.h (find_param_fuzzy): New prototype.
	* spellcheck.c (struct edit_distance_traits<const char *>): Move
	to...
	* spellcheck.h (struct edit_distance_traits<const char *>):
	...here.

gcc/testsuite/ChangeLog:
	* gcc.dg/spellcheck-params.c: New testcase.
	* gcc.dg/spellcheck-params-2.c: New testcase.

From-SVN: r237865