Remove dot in err.compat.h guard

lib/err.compat.h

@@ -16,8 +16,8 @@
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  */
 
-#ifndef ICP20110203_ERR.C_H
-#define ICP20110203_ERR.C_H
+#ifndef ICP20110203_ERR_H
+#define ICP20110203_ERR_H
 
 #include <stdarg.h>
 
@@ -45,4 +45,4 @@ void vwarnx(const char *, va_list);
 }
 #endif
 
-#endif /* !ICP20110203_ERR.C_H */
+#endif /* !ICP20110203_ERR_H */