Without this patch, you can't build nrpe without SSL support. It was
originally submitted on the Nagios forums by user Matthew L. Daniel:

  https://support.nagios.com/forum/viewtopic.php?t=27027

It was merged into the upstream github repo (NagiosEnterprises/nrpe)
in commit 3736fdeeac11a.


diff --git a/src/nrpe.c b/src/nrpe.c
index 4bc849b..1e55ab4 100644
--- a/src/nrpe.c
+++ b/src/nrpe.c
@@ -102,7 +102,9 @@ int     use_src=FALSE; /* Define parameter for SRC option */
 int		listen_queue_size=DEFAULT_LISTEN_QUEUE_SIZE;
 
 
+#ifdef HAVE_SSL
 void complete_SSL_shutdown( SSL *);
+#endif
 
 
 int main(int argc, char **argv){
@@ -1815,6 +1817,7 @@ int remove_pid_file(void){
 	return OK;
         }
 
+#ifdef HAVE_SSL
 void complete_SSL_shutdown( SSL *ssl) {
 
 	/*  
@@ -1835,6 +1838,7 @@ void complete_SSL_shutdown( SSL *ssl) {
 		if( SSL_shutdown( ssl)) break;
 	}
 }
+#endif/*HAVE_SSL*/
 
 /* bail if daemon is running as root */
 int check_privileges(void){