Updated todo list

docs/todo.md

@@ -19,16 +19,24 @@
 - [x] Multiple return values
 - [x] Data structures
 - [x] Type system
+- [ ] Dynamic libraries: Linux Mac ~~Windows~~
+- [ ] Unsigned types
 - [ ] Type operator `?`
 - [ ] Slices
 - [ ] Floating-point arithmetic
-- [ ] Error handling
-- [ ] Threading library
 - [ ] Self-hosted compiler
 
+### Library
+
+- [ ] Efficient memory allocator
+- [ ] Error handling
+- [ ] Multithreading: ~~Linux~~ Mac ~~Windows~~
+
 ### Keywords
 
 - [x] `assert`
+- [x] `const`
+- [x] `extern`
 - [x] `else`
 - [ ] `for`
 - [x] `if`
@@ -69,7 +77,7 @@
 
 ### Architecture
 
-- [ ] arm64
+- [ ] arm
 - [ ] riscv
 - [x] x86