Issue 2440: remove the guard around the handling of case 'n' in getargs.c's convertsimple() such that we always treat it as an index type, regardless of whether or not sizeof(size_t) == sizeof(long). Fix the test_args2.Signed_TestCase.test_n() such that it tests for adherence to PEP 357 (don't try and coerce objects that don't have nb_index slots but do have nb_int slots (i.e. floats) into indexes 'just because we can'). Three other commits are related to this one: r62269 and r62279, which were changes to PyNumber_Index (among other things) to check for nb_int slots when we lack nb_index slots -- and r62292, which is when I reverted these changes after various people pointed out that the test was in fact wrong, not the code.

/* Cross platform case insensitive string compare functions
 */

#include "Python.h"

int
PyOS_mystrnicmp(const char *s1, const char *s2, Py_ssize_t size)
{
	if (size == 0)
		return 0;
	while ((--size > 0) &&
	       (tolower((unsigned)*s1) == tolower((unsigned)*s2))) {
		if (!*s1++ || !*s2++)
			break;
	}
	return tolower((unsigned)*s1) - tolower((unsigned)*s2);
}

int
PyOS_mystricmp(const char *s1, const char *s2)
{
	while (*s1 && (tolower((unsigned)*s1++) == tolower((unsigned)*s2++))) {
		;
	}
	return (tolower((unsigned)*s1) - tolower((unsigned)*s2));
}