Add support for deprecated loader (bp #11946) (#12114)

* Add support for deprecated loader (#11946)


(cherry picked from commit ae0fd3043a)

* fix version

Co-authored-by: Jack May <jack@solana.com>

sdk/src/entrypoint.rs

@@ -1,4 +1,5 @@
-//! @brief Solana Rust-based BPF program entry point
+//! @brief Solana Rust-based BPF program entry point supported by the latest
+//! BPFLoader.  For more information see './bpf_loader.rs'
 
 extern crate alloc;
 use crate::{account_info::AccountInfo, program_error::ProgramError, pubkey::Pubkey};