Compile for non OpenBSD systems

Previously the compilation would fail for non OpenBSD systems & the
user had to manage it themselves. Now it compiles on non OpenBSD
systems but returns nil immediately because unveil isn't supported on
those systems.

1 files changed, 2 insertions, 0 deletions

diff --git a/block.go b/block.go
index c16a1eb..5a46693 100644
--- a/block.go
+++ b/block.go
@@ -1,3 +1,5 @@
+// +build openbsd
+
 package lynx
 
 import "golang.org/x/sys/unix"