add macOS platform support

- Add macOS example app and Xcode configuration
- Configure pubspec.yaml for macOS compatibility
- Create shell script for libthorvg.dylib generation

Author: JoMinSeo

.gitignore

@@ -32,6 +32,7 @@ pubspec.lock
 # Generated binaries
 android/src/main/jniLibs/
 ios/Frameworks/
+macos/Frameworks/
 
 # Generated android build files(.cxx)
 android/app/.cxx

example/.gitignore

@@ -5,9 +5,11 @@
 *.swp
 .DS_Store
 .atom/
+.build/
 .buildlog/
 .history
 .svn/
+.swiftpm/
 migrate_working_dir/
 
 # IntelliJ related

example/macos/.gitignore

@@ -0,0 +1,7 @@
+# Flutter-related
+**/Flutter/ephemeral/
+**/Pods/
+
+# Xcode-related
+**/dgph
+**/xcuserdata/

example/macos/Flutter/Flutter-Debug.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
+#include "ephemeral/Flutter-Generated.xcconfig"

example/macos/Flutter/Flutter-Release.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
+#include "ephemeral/Flutter-Generated.xcconfig"

example/macos/Flutter/GeneratedPluginRegistrant.swift

@@ -0,0 +1,10 @@
+//
+//  Generated file. Do not edit.
+//
+
+import FlutterMacOS
+import Foundation
+
+
+func RegisterGeneratedPlugins(registry: FlutterPluginRegistry) {
+}

example/macos/Podfile

@@ -0,0 +1,42 @@
+platform :osx, '10.14'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'ephemeral', 'Flutter-Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure \"flutter pub get\" is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Flutter-Generated.xcconfig, then run \"flutter pub get\""
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_macos_podfile_setup
+
+target 'Runner' do
+  use_frameworks!
+
+  flutter_install_all_macos_pods File.dirname(File.realpath(__FILE__))
+  target 'RunnerTests' do
+    inherit! :search_paths
+  end
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_macos_build_settings(target)
+  end
+end

example/macos/Podfile.lock

@@ -0,0 +1,22 @@
+PODS:
+  - FlutterMacOS (1.0.0)
+  - thorvg (1.0.0-beta.0):
+    - FlutterMacOS
+
+DEPENDENCIES:
+  - FlutterMacOS (from `Flutter/ephemeral`)
+  - thorvg (from `Flutter/ephemeral/.symlinks/plugins/thorvg/macos`)
+
+EXTERNAL SOURCES:
+  FlutterMacOS:
+    :path: Flutter/ephemeral
+  thorvg:
+    :path: Flutter/ephemeral/.symlinks/plugins/thorvg/macos
+
+SPEC CHECKSUMS:
+  FlutterMacOS: 8f6f14fa908a6fb3fba0cd85dbd81ec4b251fb24
+  thorvg: cd85d234f639201c8d58d80ea923e136c6deffd7
+
+PODFILE CHECKSUM: 7eb978b976557c8c1cd717d8185ec483fd090a82
+
+COCOAPODS: 1.16.2