Merge branch 'sval' into merge

Merge branch 'sval' into merge

Before smatch used "long long" to represent values.  This fails
because it isn't possible to represent ULLONG_MAX.  The sval
work solves that by always connecting the value to the type.

Instead of "long long" we now use an sval_t which is defined like
this:

typedef struct {
	struct symbol *type;
	union {
		long long value;
		unsigned long long uvalue;
	};
} sval_t;

The sval_t type has been pushed everywhere now so we always have
easy access to a struct symbol *type.

That bad news is that a lot of error messages will change formats
slightly.  In particular check_signed.c has been re-written.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>