diff --git a/modules/ssl/ssl_engine_init.c b/modules/ssl/ssl_engine_init.c
index 446d271426..5d0a835ac9 100644
--- a/modules/ssl/ssl_engine_init.c
+++ b/modules/ssl/ssl_engine_init.c
@@ -53,7 +53,7 @@ APR_IMPLEMENT_OPTIONAL_HOOK_RUN_ALL(ssl, SSL, int, init_server,
 #if OPENSSL_VERSION_NUMBER < 0x10100000L
 /* OpenSSL Pre-1.1.0 compatibility */
 /* Taken from OpenSSL 1.1.0 snapshot 20160410 */
-int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
+static int DH_set0_pqg(DH *dh, BIGNUM *p, BIGNUM *q, BIGNUM *g)
 {
     /* q is optional */
     if (p == NULL || g == NULL)