$NetBSD: patch-src_zm_comms_cpp,v 1.3 2020/08/25 16:42:21 gdt Exp $

Don't attempt to include headers that don't exist.

--- src/zm_comms.cpp.orig	2016-02-03 18:40:30.000000000 +0000
+++ src/zm_comms.cpp
@@ -28,8 +28,10 @@
 #if defined(BSD)
 #include <stdlib.h>
 #else
+#ifdef HAVE_ALLOCA_H
 #include <alloca.h>
 #endif
+#endif
 
 //#include <unistd.h>
 #include <sys/ioctl.h>