From 298085b62d5a2101d3086bede8a34b6c9ac8d019 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Fri, 25 Jun 2021 15:57:39 +0800
Subject: [PATCH] fix compilation with nixpkgs 21.05

The environment variable is optional to keep compatibility with other build environments.

Closes #131
---
 default.nix            | 1 +
 shell.nix              | 1 +
 src/libc/build.rs      | 5 +++++
 src/libunwind/build.rs | 4 ++++
 4 files changed, 11 insertions(+)

diff --git a/default.nix b/default.nix
index b36cf3f..3f146bd 100644
--- a/default.nix
+++ b/default.nix
@@ -31,6 +31,7 @@ let
       ];
       buildPhase = ''
         export XARGO_RUST_SRC="${rustPlatform.rust.rustc}/lib/rustlib/src/rust/library"
+        export CLANG_EXTRA_INCLUDE_DIR="${pkgs.llvmPackages_9.clang-unwrapped.lib}/lib/clang/9.0.1/include"
         export CARGO_HOME=$(mktemp -d cargo-home.XXX)
         make TARGET=${target} VARIANT=${variant}
       '';
diff --git a/shell.nix b/shell.nix
index e38adaa..29390fb 100644
--- a/shell.nix
+++ b/shell.nix
@@ -30,6 +30,7 @@ in
     ];
 
     XARGO_RUST_SRC = "${rustPlatform.rust.rustc}/lib/rustlib/src/rust/library";
+    CLANG_EXTRA_INCLUDE_DIR = "${pkgs.llvmPackages_9.clang-unwrapped.lib}/lib/clang/9.0.1/include";
     OPENOCD_ZYNQ = "${zynq-rs}/openocd";
     SZL = "${zc706-szl}/szl.elf";
   }
diff --git a/src/libc/build.rs b/src/libc/build.rs
index 43ab8e6..08002d9 100644
--- a/src/libc/build.rs
+++ b/src/libc/build.rs
@@ -5,6 +5,8 @@ fn main() {
 
 mod libc {
     use std::path::Path;
+    use std::env;
+
     pub fn compile() {
         let cfg = &mut cc::Build::new();
         cfg.no_default_flags(true);
@@ -16,6 +18,9 @@ mod libc {
         cfg.flag("-ffreestanding");
         cfg.flag("-fno-PIC");
         cfg.flag("-isystem../include");
+        if let Ok(extra_include) = env::var("CLANG_EXTRA_INCLUDE_DIR") {
+            cfg.flag(&("-isystem".to_owned() + &extra_include));
+        }
         cfg.flag("-fno-stack-protector");
         cfg.flag("--target=armv7-none-eabihf");
         cfg.flag("-O2");
diff --git a/src/libunwind/build.rs b/src/libunwind/build.rs
index d7f6645..51dc16c 100644
--- a/src/libunwind/build.rs
+++ b/src/libunwind/build.rs
@@ -6,6 +6,7 @@ fn main() {
 
 mod llvm_libunwind {
     use std::path::Path;
+    use std::env;
 
     fn setup_options(cfg: &mut cc::Build) {
         cfg.no_default_flags(true);
@@ -16,6 +17,9 @@ mod llvm_libunwind {
         cfg.flag("-fno-PIC");
         cfg.flag("-Isrc");
         cfg.flag("-isystem../include");
+        if let Ok(extra_include) = env::var("CLANG_EXTRA_INCLUDE_DIR") {
+            cfg.flag(&("-isystem".to_owned() + &extra_include));
+        }
         cfg.flag("-fno-stack-protector");
         cfg.flag("--target=armv7-none-eabihf");
         cfg.flag("-O2");