(ziclh lang rust): use compile-time path for yj

This will have to be replaced with a small Rust program, but I don't
want to resolve the chicken-egg problem right now.

lang/rust/default.nix

@@ -1,4 +1,4 @@
-{ chickenPackages, libsodium, callPackage, xxd }:
+{ chickenPackages, libsodium, callPackage, xxd, yj }:
 (callPackage ../../lib/build-chicken-parallel {}) {
   name = "zilch-lang-rust";
   src = ./.;
@@ -14,6 +14,8 @@
 
     xxd
   ];
+
+  overrides.NIX_CFLAGS_COMPILE = "-DYJ_PATH=\"${yj}/bin/yj\"";
   overrides.preBuild = ''
     (cat ${./helpers/src/bin/buildscript-runner.rs}; printf '\0') | xxd -i -n runner_source > runner_source.h
     (cat ${./helpers/src/bin/rustc-wrapper.rs}; printf '\0') | xxd -i -n rustc_wrap_source > rustc_wrap_source.h

lang/rust/src/cargo.sld

@@ -44,10 +44,11 @@
 
  (begin
    (define linker (delay (let ((v (cdr (assoc "out" (nixpkgs "gcc"))))) #~,(string-append #$v "/bin/cc"))))
+   (define yj-path (foreign-value "YJ_PATH" nonnull-c-string))
 
    ;; Shell out to a TOML-to-JSON parser. This will be replaced with a Nix-native solution later(tm).
    (define (parse-toml toml-to-parse)
-     (define-values (read-port write-port pid) (process "yj" '("yj" "-tj")))
+     (define-values (read-port write-port pid) (process yj-path '("yj" "-tj")))
      (write-string toml-to-parse write-port)
      (close-output-port write-port)
      (define parsed (json-read read-port))

lang/rust/src/registry.sld

@@ -15,9 +15,11 @@
    lockfile-entry? lockfile-entry-name lockfile-entry-version lockfile-entry-source lockfile-entry-checksum lockfile-entry-dependencies)
 
  (begin
+   (define yj-path (foreign-value "YJ_PATH" nonnull-c-string))
+
    ;; Shell out to a TOML-to-JSON parser. This will be replaced with a Nix-native solution later(tm).
    (define (parse-toml toml-to-parse)
-     (define-values (read-port write-port pid) (process "yj" '("yj" "-tj")))
+     (define-values (read-port write-port pid) (process yj-path '("yj" "-tj")))
      (write-string toml-to-parse write-port)
      (close-output-port write-port)
      (define parsed (json-read read-port))

shell.nix

@@ -27,7 +27,6 @@ pkgs.mkShell {
     pkgs.nodejs
     pkgs.bpftrace
     pkgs.s6
-    pkgs.yj
 
     pkgs.rlwrap
   ];