diff --git a/ext/gvl_wrappers.c b/ext/gvl_wrappers.c
index b949fd891..eee8ff5ba 100644
--- a/ext/gvl_wrappers.c
+++ b/ext/gvl_wrappers.c
@@ -5,6 +5,10 @@
 
 #include "pg.h"
 
+#ifndef HAVE_PQENCRYPTPASSWORDCONN
+char *PQencryptPasswordConn(PGconn *conn, const char *passwd, const char *user, const char *algorithm){return NULL;}
+#endif
+
 FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_WRAPPER_STRUCT );
 FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_SKELETON );
 FOR_EACH_BLOCKING_FUNCTION( DEFINE_GVL_STUB );
diff --git a/ext/gvl_wrappers.h b/ext/gvl_wrappers.h
index 7e46f8f26..bf6446155 100644
--- a/ext/gvl_wrappers.h
+++ b/ext/gvl_wrappers.h
@@ -24,10 +24,6 @@ extern void *rb_thread_call_without_gvl(void *(*func)(void *), void *data1,
 				 rb_unblock_function_t *ubf, void *data2);
 #endif
 
-#ifndef HAVE_PQENCRYPTPASSWORDCONN
-extern char *PQencryptPasswordConn(PGconn *conn, const char *passwd, const char *user, const char *algorithm);
-#endif
-
 #define DEFINE_PARAM_LIST1(type, name) \
 	name,