[ Upstream commitc485ca3aff] There is no errno variable when NOLIBC_IGNORE_ERRNO is defined. As such, simply print the message with "unknown error" rather than the integer value of errno. Fixes:acab7bcdb1("tools/nolibc/stdio: add perror() to report the errno value") Signed-off-by: Benjamin Berg <benjamin.berg@intel.com> Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Signed-off-by: Sasha Levin <sashal@kernel.org>