bpo-42960: Add resource.RLIMIT_KQUEUES constant from FreeBSD (GH-24251)

diff --git a/Modules/resource.c b/Modules/resource.c
index f10a80f..0d69c29 100644
--- a/Modules/resource.c
+++ b/Modules/resource.c
@@ -480,6 +480,10 @@ resource_exec(PyObject *module)
     ADD_INT(module, RLIMIT_NPTS);
 #endif
 
+#ifdef RLIMIT_KQUEUES
+    ADD_INT(module, RLIMIT_KQUEUES);
+#endif
+
     PyObject *v;
     if (sizeof(RLIM_INFINITY) > sizeof(long)) {
         v = PyLong_FromLongLong((long long) RLIM_INFINITY);