when resolving symbols with only weak defs, use first def, not last def

[musl] / src / string / wcspbrk.c

#include <wchar.h>

wchar_t *wcspbrk(const wchar_t *s, const wchar_t *b)
{
        s += wcscspn(s, b);
        return *s ? (wchar_t *)s : NULL;
}