Add optional dependencies to Brewfile and improve CMake configuration

This commit updates the Brewfile to include additional optional dependencies such as Vulkan headers, RapidJSON, and various libraries for enhanced functionality. It also modifies CMake files to make the handling of optional components more user-friendly, allowing missing dependencies to disable features without causing build failures on macOS. Additionally, it refines the search paths for the Sparkle framework and adjusts the linking of the discord-rpc library based on the availability of RapidJSON.

Formula/sparkle-framework.rb

@@ -0,0 +1,19 @@
+class SparkleFramework < Formula
+  desc "Sparkle.framework for macOS app updates (framework-only packaging)"
+  homepage "https://sparkle-project.org/"
+  url "https://github.com/sparkle-project/Sparkle/releases/download/2.8.1/Sparkle-2.8.1.tar.xz"
+  sha256 "5cddb7695674ef7704268f38eccaee80e3accbf19e61c1689efff5b6116d85be"
+  license "MIT"
+
+  depends_on :macos
+
+  def install
+    frameworks = prefix/"Frameworks"
+    frameworks.install "Sparkle.framework"
+  end
+
+  test do
+    assert_predicate prefix/"Frameworks/Sparkle.framework", :exist?
+  end
+end
+