GDC mainline (20221219) fails to build on OpenBSD (patch included)

[Brian Callahan]

Hi Iain --

GDC mainline stopped building on OpenBSD recently. Below is the 
diff to fix things.

Thanks.

~Brian

diff --git a/libphobos/libdruntime/core/demangle.d 
b/libphobos/libdruntime/core/demangle.d
index 869ade64821..30e38c76479 100644
--- a/libphobos/libdruntime/core/demangle.d
+++ b/libphobos/libdruntime/core/demangle.d
@@ -2929,6 +2929,7 @@ CXX_DEMANGLER getCXXDemangler() nothrow 
@trusted
          version (FreeBSD) import core.sys.freebsd.dlfcn : 
RTLD_DEFAULT;
          version (linux) import core.sys.linux.dlfcn : 
RTLD_DEFAULT;
          version (NetBSD) import core.sys.netbsd.dlfcn : 
RTLD_DEFAULT;
+        version (OpenBSD) import core.sys.openbsd.dlfcn : 
RTLD_DEFAULT;
          version (OSX) import core.sys.darwin.dlfcn : 
RTLD_DEFAULT;
          version (Solaris) import core.sys.solaris.dlfcn : 
RTLD_DEFAULT;