From 864ae3b936e9c9fe87e9307162ffbc73a564d287 Mon Sep 17 00:00:00 2001
From: Folkert <folkert@folkertdev.nl>
Date: Thu, 14 Jul 2022 12:11:42 +0200
Subject: [PATCH] wasi-libc-sys: use environment variables to translate from
 build.rs to a const, instead of rust code generation

---
 crates/wasi-libc-sys/.gitignore |  1 -
 crates/wasi-libc-sys/build.rs   | 24 ++++++++----------------
 crates/wasi-libc-sys/src/lib.rs |  6 ++++--
 3 files changed, 12 insertions(+), 19 deletions(-)
 delete mode 100644 crates/wasi-libc-sys/.gitignore

diff --git a/crates/wasi-libc-sys/.gitignore b/crates/wasi-libc-sys/.gitignore
deleted file mode 100644
index 9802e8fdbf..0000000000
--- a/crates/wasi-libc-sys/.gitignore
+++ /dev/null
@@ -1 +0,0 @@
-src/generated.rs
diff --git a/crates/wasi-libc-sys/build.rs b/crates/wasi-libc-sys/build.rs
index 0029ad53b8..cfc9f6fefa 100644
--- a/crates/wasi-libc-sys/build.rs
+++ b/crates/wasi-libc-sys/build.rs
@@ -40,23 +40,15 @@ fn main() {
     // Copy libc to where Cargo expects the output of this crate
     fs::copy(&libc_path, &out_file).unwrap();
 
-    // Generate some Rust code to indicate where the file is
-    let generated_rust = [
-        "pub const WASI_LIBC_PATH: &str =",
-        &format!(
-            "    \"{}\";",
-            out_file.to_str().unwrap().replace('\\', "\\\\")
-        ),
-        "pub const WASI_COMPILER_RT_PATH: &str =",
-        &format!(
-            "  \"{}\";",
-            compiler_rt_path.to_str().unwrap().replace('\\', "\\\\")
-        ),
-        "",
-    ]
-    .join("\n");
+    println!(
+        "cargo:rustc-env=WASI_LIBC_PATH=\"{}\"",
+        out_file.to_str().unwrap().replace('\\', "\\\\")
+    );
 
-    fs::write("src/generated.rs", generated_rust).unwrap();
+    println!(
+        "cargo:rustc-env=WASI_COMPILER_RT_PATH=\"{}\"",
+        compiler_rt_path.to_str().unwrap().replace('\\', "\\\\")
+    );
 }
 
 fn zig_executable() -> String {
diff --git a/crates/wasi-libc-sys/src/lib.rs b/crates/wasi-libc-sys/src/lib.rs
index bc487bd282..e0322e6d16 100644
--- a/crates/wasi-libc-sys/src/lib.rs
+++ b/crates/wasi-libc-sys/src/lib.rs
@@ -14,5 +14,7 @@ extern "C" {
 // Tell users of this crate where to find the Wasm .a file
 // If a non-Wasm target is using this crate, we assume it is a build script that wants to emit Wasm
 // For Wasm target, it won't ever be used, but we expose it just to keep things simple
-mod generated;
-pub use generated::{WASI_COMPILER_RT_PATH, WASI_LIBC_PATH};
+
+// these variables are set by build.rs
+pub const WASI_LIBC_PATH: &str = env!("WASI_LIBC_PATH");
+pub const WASI_COMPILER_RT_PATH: &str = env!("WASI_COMPILER_RT_PATH");