Consider nil as null?

CHANGELOG.md

@@ -3,6 +3,7 @@ All notable changes to this project will be documented in this file. This change
 
 ## [Unreleased]
 ### Fixed
+- `nil` was not considered a null pointer
 - Primitive-serializing types fail to compile as arguments to downcall handles
 - Primitive-serializing types fail to load as arguments to upcall functions
 - Void return types on upcalls crash the JVM

src/clj/coffi/mem.clj

@@ -128,7 +128,7 @@
 (defn null?
   "Checks if a memory address is null."
   [addr]
-  (.equals (MemoryAddress/NULL) addr))
+  (or (.equals (MemoryAddress/NULL) addr) (not addr)))
 
 (defn slice-global
   "Gets a slice of the global address space.