1 files changed, 5 insertions, 0 deletions

diff --git a/src/lib/libcrypto/pqueue/pq_compat.h b/src/lib/libcrypto/pqueue/pq_compat.h
index fd36578882..7b2c32725c 100644
--- a/src/lib/libcrypto/pqueue/pq_compat.h
+++ b/src/lib/libcrypto/pqueue/pq_compat.h
@@ -57,6 +57,9 @@
  *
  */
 
+#ifndef HEADER_PQ_COMPAT_H
+#define HEADER_PQ_COMPAT_H
+
 #include <openssl/opensslconf.h>
 #include <openssl/bn.h>
 
@@ -145,3 +148,5 @@
                                               *(x) |= mask; \
                                           } while(0)
 #endif /* OPENSSL_SYS_VMS */
+
+#endif