$OpenBSD$

Index: runtime/druntime/src/core/stdc/config.d
--- runtime/druntime/src/core/stdc/config.d.orig
+++ runtime/druntime/src/core/stdc/config.d
@@ -116,6 +116,8 @@ else version( DigitalMars )
             alias real c_long_double;
         else version( FreeBSD )
             alias real c_long_double;
+        else version( OpenBSD )
+            alias real c_long_double;
         else version( DragonFlyBSD )
             alias real c_long_double;
         else version( Solaris )
