Add support for GNU Hurd

Corresponding to flashrom svn r1948.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006@gmx.net>
diff --git a/os.h b/os.h
index e5f72e4..b59e087 100644
--- a/os.h
+++ b/os.h
@@ -56,6 +56,9 @@
 // libpayload
 #elif defined(__LIBPAYLOAD__)
 #define __FLASHROM_OS__ "libpayload"
+// GNU Hurd
+#elif defined(__gnu_hurd__)
+#define __FLASHROM_OS__ "Hurd"
 // Linux
 #elif defined(__linux__)
 	// There are various flags in use on Android apparently. __ANDROID__ seems to be the most trustworthy.