$OpenBSD$

Index: runtime/druntime/src/core/sys/posix/sys/ioctl.d
--- runtime/druntime/src/core/sys/posix/sys/ioctl.d.orig
+++ runtime/druntime/src/core/sys/posix/sys/ioctl.d
@@ -359,6 +359,18 @@ else version (FreeBSD)
 
     int ioctl(int, c_ulong, ...);
 }
+else version (OpenBSD)
+{
+    struct winsize
+    {
+        ushort ws_row;
+        ushort ws_col;
+        ushort ws_xpixel;
+        ushort ws_ypixel;
+    }
+
+    int ioctl(int, c_ulong, ...);
+}
 else version (DragonFlyBSD)
 {
     struct fiodgname_arg
