allocator interface (first pass)

README.md

@@ -71,7 +71,8 @@ main func() void {
 
 Header imports expose supported external functions, typedefs, C scalars, fixed
 arrays, complete plain structs and unions, function pointer typedefs, and
-pointers to opaque records. Plain records can be constructed with keyed
+pointers to opaque records. C `void*` imports as nullable `anyopaque` pointers.
+Plain records can be constructed with keyed
 literals, accessed by field, and passed or returned by value through fixed C
 signatures on `aarch64-macos`. Unsupported or incomplete records remain
 pointer-only. Header imports never add linker inputs; implementations must still
@@ -154,7 +155,7 @@ declares them. Imports beginning with `@` resolve from the project root:
 ```bro
 import "../math"
 other_math :: import "../math"
-heap :: import "@std/mem/heap"
+mem :: import "@std/mem"
 
 value :: math.sum(other_math.value, 1)
 ```
@@ -165,7 +166,7 @@ Current prototype features:
 - `#` comments
 - Immutable `::` bindings, typed mutable `=` locals/globals, and `_` sinks
 - Exact-width signed/unsigned integers, `f32`, `f64`, `isize`, `usize`, and loose integer-constrained `int`
-- Target-dependent atomic `c_*` primitive types, `c_func`, and defined or opaque `c_struct`
+- Target-dependent atomic `c_*` primitive types, `c_func`, complete `c_struct`, `opaque`, `anyopaque`, and V1 `ptr_cast(T, ptr)`
 - Arrays, sentinel arrays, single-item pointers, many-item pointers, sentinel many-item pointers, slices, sentinel slices, strings, character literals, optionals, and native structs
 - String literals as immutable pointers to static zero-terminated byte arrays
 - Pointer-preserving `.ptr`/`.len`, pointer-to-array indexing and slicing, postfix pointer dereference and optional unwrap, and keyed struct literals