+ * optimization: slightly faster gc on multithreaded builds
+ * optimization: faster WITHOUT-GCING
+ * bug fix: when JOIN-THREAD signals an error, do it when not holding
+ important locks so that the debugger/handler doesn't produce
+ recursive errors or deadlock.
+ * bug fix: real-time signals are not used anymore, so no more
+ hanging when the system wide real-time signal queue gets full.
+ * bug fix: finalizers, gc hooks never run in a WITHOUT-INTERRUPTS
+ * bug fix: fix deadlocks related to starting threads