allocator interface (first pass)

std/mem/heap/heap.bro

@@ -1,6 +1,9 @@
-malloc c_func(size usize) ?*mut u8
-free c_func(ptr ?*mut u8) void
+mem :: import ".."
 
 alloc func(size usize) ?*mut u8 {
-	return malloc(size)
+	return mem.alloc(mem.heap, size, 1)
+}
+
+free func(memory ?*mut u8) void {
+	mem.free(mem.heap, memory, 0, 1)
 }