diff --git a/lib/compiler/configurer.zig b/lib/compiler/configurer.zig
index 4990478ac2..9ae2ab0a0e 100644
--- a/lib/compiler/configurer.zig
+++ b/lib/compiler/configurer.zig
@@ -859,7 +859,28 @@ fn serialize(b: *std.Build, wc: *Configuration.Wip, writer: *Io.Writer) !void {
                             .dest_sub_path = try wc.addString(sif.dest_rel_path),
                         })));
                     },
-                    .install_dir => @panic("TODO"),
+                    .install_dir => e: {
+                        const sid: *Step.InstallDir = @fieldParentPtr("step", step);
+                        const dest_sub_path: ?[]const u8 = if (sid.options.install_subdir.len != 0)
+                            sid.options.install_subdir
+                        else
+                            null;
+                        const include_extensions = sid.options.include_extensions orelse &.{};
+                        break :e @enumFromInt(try wc.addExtra(@as(Configuration.Step.InstallDir, .{
+                            .flags = .{
+                                .dest_sub_path = dest_sub_path != null,
+                                .exclude_extensions = sid.options.exclude_extensions.len != 0,
+                                .include_extensions = include_extensions.len != 0,
+                                .blank_extensions = sid.options.blank_extensions.len != 0,
+                            },
+                            .source_dir = try s.addLazyPath(sid.options.source_dir),
+                            .dest_dir = try addInstallDir(wc, sid.options.install_dir),
+                            .dest_sub_path = .{ .value = try s.addOptionalString(dest_sub_path) },
+                            .exclude_extensions = .{ .slice = try s.initStringList(sid.options.exclude_extensions) },
+                            .include_extensions = .{ .slice = try s.initStringList(include_extensions) },
+                            .blank_extensions = .{ .slice = try s.initStringList(sid.options.blank_extensions) },
+                        })));
+                    },
                     .remove_dir => @panic("TODO"),
                     .fail => e: {
                         const sf: *Step.Fail = @fieldParentPtr("step", step);
diff --git a/lib/std/Build/Configuration.zig b/lib/std/Build/Configuration.zig
index f9cd339711..33e583402e 100644
--- a/lib/std/Build/Configuration.zig
+++ b/lib/std/Build/Configuration.zig
@@ -210,9 +210,11 @@ pub const Wip = struct {
     }
 
     pub fn addBytes(wip: *Wip, bytes: []const u8) Allocator.Error!Bytes {
-        _ = wip;
-        _ = bytes;
-        @panic("TODO");
+        try wip.string_bytes.appendSlice(wip.gpa, bytes);
+        return .{
+            .index = @intCast(wip.string_bytes.items.len - bytes.len),
+            .len = @intCast(bytes.len),
+        };
     }
 
     pub fn addSemVer(wip: *Wip, sv: std.SemanticVersion) Allocator.Error!String {