1 files changed, 2 insertions, 0 deletions
diff --git a/build.zig b/build.zig
index 79de8a81..b43f3fd9 100644
--- a/build.zig
+++ b/build.zig
@@ -752,6 +752,8 @@ pub fn build(b: *std.Build) void {
     for ([_]?*std.Build.Step.Options{ opts, gui_opts }) |maybe| if (maybe) |o| {
         o.addOption([]const []const u8, "module_names", mod_names);
         o.addOption([]const []const u8, "module_roots", mod_roots);
+        // Whose imports those are: a .zig file outside this tree has none of them.
+        o.addOption([]const u8, "project_root", b.build_root.path orelse "");
     };
 
     const iso_off = b.addOptions();