From ad34d109511aaf3eda1e666f61fb087fc891456d Mon Sep 17 00:00:00 2001
From: Austin Seipp <aseipp@pobox.com>
Date: Thu, 4 Apr 2024 01:35:05 -0500
Subject: [PATCH] nix: parallel `rustc` frontend in devShell

Only active within `devShell`; the default `.#jujutsu` package is unaffected
by this change. This somewhat increases CPU utilization and has a marginal
improvement on my local compile times, but it's also nice if you have to
recompile from scratch too.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Change-Id: I07ab28991843ca3723185569db5f38f2ed076875
---
 flake.nix | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/flake.nix b/flake.nix
index 07288ca88..4a3bdfd93 100644
--- a/flake.nix
+++ b/flake.nix
@@ -175,8 +175,10 @@
           export RUST_BACKTRACE=1
           export ZSTD_SYS_USE_PKG_CONFIG=1
           export LIBSSH2_SYS_USE_PKG_CONFIG=1
+
+          export RUSTFLAGS="-Zthreads=0"
         '' + pkgs.lib.optionalString useMoldLinker ''
-          export RUSTFLAGS="-C link-arg=-fuse-ld=mold"
+          export RUSTFLAGS+=" -C link-arg=-fuse-ld=mold"
         '' + darwinNextestHack;
       };
     }));