Add Flutter example for speaker identification (#894)

sherpa-onnx/flutter/macos/sherpa_onnx.podspec

@@ -0,0 +1,27 @@
+#
+# To learn more about a Podspec see http://guides.cocoapods.org/syntax/podspec.html.
+# Run `pod lib lint hello.podspec` to validate before publishing.
+#
+Pod::Spec.new do |s|
+  s.name             = 'sherpa_onnx'
+  s.version          = '0.0.1'
+  s.summary          = 'sherpa-onnx Flutter FFI plugin project.'
+  s.description      = <<-DESC
+sherpa-onnx Flutter FFI plugin project.
+                       DESC
+  s.homepage         = 'https://github.com/k2-fsa/sherpa-onnx'
+  s.license          = { :file => '../LICENSE' }
+  s.author           = { 'Your Company' => 'email@example.com' }
+
+  # This will ensure the source files in Classes/ are included in the native
+  # builds of apps using this FFI plugin. Podspec does not support relative
+  # paths, so Classes contains a forwarder C file that relatively imports
+  # `../src/*` so that the C sources can be shared among all target platforms.
+  s.source           = { :path => '.' }
+  s.dependency 'FlutterMacOS'
+  s.vendored_libraries = '*.dylib'
+
+  s.platform = :osx, '10.11'
+  s.pod_target_xcconfig = { 'DEFINES_MODULE' => 'YES' }
+  s.swift_version = '5.0'
+end