--- mesonbuild/envconfig.py.orig	2020-06-15 05:40:08.000000000 +1000
+++ mesonbuild/envconfig.py	2020-08-26 12:00:08.194425000 +1000
@@ -285,6 +285,10 @@
         """Machine is DragonflyBSD?"""
         return self.system == 'dragonfly'
 
+    def is_bsdsunix(self) -> bool:
+        """Machine is BSDSUniX?"""
+        return self.system == 'bsdsunix'
+
     def is_freebsd(self) -> bool:
         """Machine is FreeBSD?"""
         return self.system == 'freebsd'