Add preliminary support for Windows .manifest files

Author: squeek502

lib/std/Build/Step/Compile.zig

@@ -257,6 +257,7 @@ pub const LinkObject = union(enum) {
     c_source_file: *CSourceFile,
     c_source_files: *CSourceFiles,
     win32_resource_file: *RcSourceFile,
+    win32_manifest_file: LazyPath,
 };
 
 pub const SystemLib = struct {
@@ -952,6 +953,17 @@ pub fn addWin32ResourceFile(self: *Compile, source: RcSourceFile) void {
     source.file.addStepDependencies(&self.step);
 }
 
+pub fn addWin32ManifestFile(self: *Compile, source: LazyPath) void {
+    // Only the PE/COFF format has a Resource Table which is where the manifest
+    // gets embedded, so for any other target the manifest file is just ignored.
+    if (self.target.getObjectFormat() != .coff) return;
+
+    const b = self.step.owner;
+    const source_duped = source.dupe(b);
+    self.link_objects.append(.{ .win32_manifest_file = source_duped }) catch @panic("OOM");
+    source.addStepDependencies(&self.step);
+}
+
 pub fn setVerboseLink(self: *Compile, value: bool) void {
     self.verbose_link = value;
 }
@@ -1567,6 +1579,10 @@ fn make(step: *Step, prog_node: *std.Progress.Node) !void {
                 }
                 try zig_args.append(rc_source_file.file.getPath(b));
             },
+
+            .win32_manifest_file => |manifest_file| {
+                try zig_args.append(manifest_file.getPath(b));
+            },
         }
     }