feat: verifiable-build.toml to specify solana version

Author: Arrowana

README.md

@@ -25,6 +25,15 @@ Verified builds allow developers and users to verify that a deployed Solana prog
 solana-verify build
 ```
 
+For minimal programs that do not depend on `solana-program`, add a
+`verifiable-build.toml` file at the program root:
+
+```toml
+solana_version = "2.1.8"
+```
+
+If `--base-image` is provided, `verifiable-build.toml` is ignored.
+
 3. Deploy and verify:
 
 ```bash

examples/hello_world_pinocchio/Cargo.lock

@@ -0,0 +1,17 @@
+[package]
+name = "hello_world"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+crate-type = ["cdylib", "lib"]
+name = "hello_world"
+
+[dependencies]
+pinocchio = "0.10.1" 
+solana-program-log = "1.1.0"
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = [
+    'cfg(target_os, values("solana"))',
+] }

examples/hello_world_pinocchio/Cargo.toml

@@ -0,0 +1,13 @@
+use pinocchio::{program_entrypoint, AccountView, Address, ProgramResult};
+use solana_program_log::log;
+
+program_entrypoint!(process_instruction);
+
+fn process_instruction(
+    _program_id: &Address,
+    _accounts: &[AccountView],
+    _instruction_data: &[u8],
+) -> ProgramResult {
+    log("Hello, world!");
+    Ok(())
+}

examples/hello_world_pinocchio/src/lib.rs

@@ -0,0 +1 @@
+solana_version = "3.0.7"