Fix #1606 (Call runtime._cleanup_runtime_contextless() for os.exit)

core/os/os_openbsd.odin

@@ -5,6 +5,7 @@ foreign import libc "system:c"
 import "core:runtime"
 import "core:strings"
 import "core:c"
+import "core:runtime"
 
 Handle    :: distinct i32
 Pid       :: distinct i32
@@ -658,6 +659,7 @@ set_current_directory :: proc(path: string) -> (err: Errno) {
 }
 
 exit :: proc "contextless" (code: int) -> ! {
+	runtime._cleanup_runtime_contextless()
 	_unix_exit(c.int(code))
 }