diff --git a/src/util/funcs.zig b/src/util/funcs.zig
index a7fbad06c8720c20bd76db354b4033c40157e808..d2bb2ee5d5c56a4994455efbe7951d09575b8e27 100644
--- a/src/util/funcs.zig
+++ b/src/util/funcs.zig
@@ -256,7 +256,7 @@ pub fn detect_pkgname(alloc: std.mem.Allocator, override: string, dir: string) !
     if (!(try does_file_exist(dirO, "build.zig"))) {
         return error.NoBuildZig;
     }
-    const dpath = try std.fs.realpathAlloc(alloc, try std.mem.concat(alloc, u8, &.{ dir, "build.zig" }));
+    const dpath = try std.fs.realpathAlloc(alloc, try std.fs.path.join(alloc, &.{ dir, "build.zig" }));
     const splitP = try split(alloc, dpath, std.fs.path.sep_str);
     var name = splitP[splitP.len - 2];
     name = trim_prefix(name, "zig-");