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

[musl] / src / internal / libc.c

#include "libc.h"

#ifdef USE_LIBC_ACCESSOR
struct __libc *__libc_loc()
{
        static struct __libc __libc;
        return &__libc;
}
#else
struct __libc __libc;
#endif