check if lld is available before using in RUSTFLAGS

justfile

@@ -1,14 +1,9 @@
-# load any variables in .env 
 set dotenv-load := true
-
-# version of rustc used for cargo commands
 rustc-version := "nightly"
-
-# name of crate registry to publish versions of this tool to
 publish-registry := "shipyard-rs-public"
 
-# env settings exported for cargo settings
-export RUSTFLAGS := "-C link-arg=-fuse-ld=lld -C target-cpu=native"
+# complicated/ugly one-liner to use lld linker if it's available
+export RUSTFLAGS := `LLD=$(which lld) && test $? -eq "0" && echo "-C link-arg=-fuse-ld=lld" || echo ''`
 
 # cargo wrapper; executes a cargo command using the settings in justfile (RUSTFLAGS, etc.)
 cargo +args='':