libuuid: add header file guard [lgtm scan]

Signed-off-by: Karel Zak <kzak@redhat.com>

libuuid/src/uuidP.h

@@ -31,6 +31,8 @@
  * DAMAGE.
  * %End-Header%
  */
+#ifndef _UUID_UUID_PRIVATE_H
+#define _UUID_UUID_PRIVATE_H
 
 #include <inttypes.h>
 #include <sys/types.h>
@@ -88,3 +90,5 @@ struct uuid {
  */
 void uuid_pack(const struct uuid *uu, uuid_t ptr);
 void uuid_unpack(const uuid_t in, struct uuid *uu);
+
+#endif /* _UUID_UUID_PRIVATE_H */