Add rust bpf allocator (#4426)

sdk/bpf/rust-utils/src/lib.rs

@@ -1,7 +1,13 @@
 //! @brief Solana Rust-based BPF program utility functions and types
 
 #![no_std]
+#![feature(allocator_api)]
+#![feature(alloc_error_handler)]
 
+pub mod alloc;
 pub mod entrypoint;
 pub mod log;
 pub mod panic;
+
+#[global_allocator]
+static A: alloc::Allocator = alloc::Allocator;