Detecting the type of sys_errlist?

[Stephane Bortzmeyer]

Does anyone have an already existing macro to check the types of sys_nerr and 
sys_errlist? My hand-crafted config.h contains:


/* These entities should be in errno.h but some systems do not define
   them. */
#ifdef sun
extern int sys_nerr;
extern char *sys_errlist[];
/* Solaris */
#ifdef __svr4__
/* Nothing specific yet */
#endif  /* SVR4 */
#endif  /* Sun */
#ifdef _AIX
extern char *sys_nerr[];
extern char *sys_errlist[];
#endif


And I would like to rewrite it with autoconf.