From 95490ff56eb274f8dea58c79a2d33e4f2713d8c8 Mon Sep 17 00:00:00 2001
From: Aaron Hill <aa1ronham@gmail.com>
Date: Tue, 14 Jul 2020 14:06:01 -0400
Subject: [PATCH] Apply #![feature(proc_macro_hygiene)] when needed

This allows the rust-bpf-builder toolchain to build the sdk
---
 sdk/build.rs   | 5 +++++
 sdk/src/lib.rs | 1 +
 2 files changed, 6 insertions(+)

diff --git a/sdk/build.rs b/sdk/build.rs
index e17ca70cb4..c9550c1c5c 100644
--- a/sdk/build.rs
+++ b/sdk/build.rs
@@ -17,6 +17,11 @@ fn main() {
         }
         Channel::Dev => {
             println!("cargo:rustc-cfg=RUSTC_WITH_SPECIALIZATION");
+            // See https://github.com/solana-labs/solana/issues/11055
+            // We may be running the custom `rust-bpf-builder` toolchain,
+            // which currently needs `#![feature(proc_macro_hygiene)]` to
+            // be applied.
+            println!("cargo:rustc-cfg=RUSTC_NEEDS_PROC_MACRO_HYGIENE");
         }
     }
 }
diff --git a/sdk/src/lib.rs b/sdk/src/lib.rs
index 0268e705ce..12fbe3909a 100644
--- a/sdk/src/lib.rs
+++ b/sdk/src/lib.rs
@@ -1,4 +1,5 @@
 #![cfg_attr(RUSTC_WITH_SPECIALIZATION, feature(specialization))]
+#![cfg_attr(RUSTC_NEEDS_PROC_MACRO_HYGIENE, feature(proc_macro_hygiene))]
 
 // Allows macro expansion of `use ::solana_sdk::*` to work within this crate
 extern crate self as solana_sdk;