$NetBSD: patch-Makefile.am,v 1.1 2021/01/09 12:53:45 rxg Exp $

Compatible with NetBSD.

--- Makefile.am.orig	2021-01-07 13:42:30.818799315 +0000
+++ Makefile.am
@@ -47,6 +47,11 @@ endif
 CFLAGS += -Wno-unused-parameter -Wno-unused-variable -Wno-null-pointer-arithmetic
 CFLAGS += -Wno-deprecated-declarations -Wno-format-nonliteral
 
+# Set flags for NetBSD.
+if IS_NETBSD
+CPPFLAGS += -D_OPENBSD_SOURCE
+endif
+
 # Set flags for Solaris.
 if IS_SUNOS
 if IS_GCC