errno.h\include - musl - musl - an implementation of the standard library for Linux-based systems

#ifndef	_ERRNO_H
#define _ERRNO_H
#ifdef __cplusplus
extern "C" {
#endif
#include <bits/errno.h>
#ifdef __GNUC__
__attribute__((const))
#endif
int *__errno_location(void);
#define errno (*__errno_location())
#ifdef __cplusplus
}
#endif
#endif