Merge pull request #21162 from maribu/sys/tiny_strerror/fix-compilati…

…on-picolibc-ubuntu

sys/tiny_strerror: fix compilation with picolibc on Ubuntu

sys/tiny_strerror/tiny_strerror.c

@@ -48,7 +48,9 @@ static FLASH_ATTR const char _edquot[] = "-EDQUOT";
 static FLASH_ATTR const char _eexist[] = "-EEXIST";
 static FLASH_ATTR const char _efault[] = "-EFAULT";
 static FLASH_ATTR const char _efbig[] = "-EFBIG";
+#ifdef EHOSTDOWN /* not part of POSIX and not universally available */
 static FLASH_ATTR const char _ehostdown[] = "-EHOSTDOWN";
+#endif
 static FLASH_ATTR const char _ehostunreach[] = "-EHOSTUNREACH";
 static FLASH_ATTR const char _eidrm[] = "-EIDRM";
 static FLASH_ATTR const char _eilseq[] = "-EILSEQ";
@@ -93,7 +95,9 @@ static FLASH_ATTR const char _enxio[] = "-ENXIO";
 static FLASH_ATTR const char _eoverflow[] = "-EOVERFLOW";
 static FLASH_ATTR const char _eownerdead[] = "-EOWNERDEAD";
 static FLASH_ATTR const char _eperm[] = "-EPERM";
+#ifdef EPFNOSUPPORT /* not part of POSIX and not universally available */
 static FLASH_ATTR const char _epfnosupport[] = "-EPFNOSUPPORT";
+#endif
 static FLASH_ATTR const char _epipe[] = "-EPIPE";
 static FLASH_ATTR const char _eprotonosupport[] = "-EPROTONOSUPPORT";
 static FLASH_ATTR const char _eprototype[] = "-EPROTOTYPE";
@@ -105,7 +109,9 @@ static FLASH_ATTR const char _esrch[] = "-ESRCH";
 static FLASH_ATTR const char _estale[] = "-ESTALE";
 static FLASH_ATTR const char _etimedout[] = "-ETIMEDOUT";
 static FLASH_ATTR const char _etime[] = "-ETIME";
+#ifdef ETOOMANYREFS /* not part of POSIX and not universally available */
 static FLASH_ATTR const char _etoomanyrefs[] = "-ETOOMANYREFS";
+#endif
 static FLASH_ATTR const char _etxtbsy[] = "-ETXTBSY";
 static FLASH_ATTR const char _exdev[] = "-EXDEV";
 /* EAGAIN and EWOULDBLOCK have the exact same meaning and consequently may
@@ -143,7 +149,9 @@ static FLASH_ATTR const char * FLASH_ATTR const lookup[] = {
     [EEXIST]            = _eexist,
     [EFAULT]            = _efault,
     [EFBIG]             = _efbig,
+#ifdef EHOSTDOWN /* not part of POSIX and not universally available */
     [EHOSTDOWN]         = _ehostdown,
+#endif
     [EHOSTUNREACH]      = _ehostunreach,
     [EIDRM]             = _eidrm,
     [EILSEQ]            = _eilseq,
@@ -188,7 +196,9 @@ static FLASH_ATTR const char * FLASH_ATTR const lookup[] = {
     [EOVERFLOW]         = _eoverflow,
     [EOWNERDEAD ]       = _eownerdead,
     [EPERM]             = _eperm,
+#ifdef EPFNOSUPPORT /* not part of POSIX and not universally available */
     [EPFNOSUPPORT]      = _epfnosupport,
+#endif
     [EPIPE]             = _epipe,
     [EPROTONOSUPPORT]   = _eprotonosupport,
     [EPROTOTYPE]        = _eprototype,
@@ -200,7 +210,9 @@ static FLASH_ATTR const char * FLASH_ATTR const lookup[] = {
     [ESTALE]            = _estale,
     [ETIMEDOUT]         = _etimedout,
     [ETIME]             = _etime,
+#ifdef ETOOMANYREFS /* not part of POSIX and not universally available */
     [ETOOMANYREFS]      = _etoomanyrefs,
+#endif
     [ETXTBSY]           = _etxtbsy,
     [EXDEV]             = _exdev,
 #if EAGAIN != EWOULDBLOCK