math: fix expf(-NAN) and exp2f(-NAN) to return -NAN instead of 0

[musl] / src / multibyte / mbsinit.c

/* 
 * This code was written by Rich Felker in 2010; no copyright is claimed.
 * This code is in the public domain. Attribution is appreciated but
 * unnecessary.
 */

#include <wchar.h>

int mbsinit(const mbstate_t *st)
{
        return !st || !*(unsigned *)st;
}