Enable SPM support for Ext and configure pipelines for extensions target testing (#3)

* initial ext files

* add a workable version of spm for extensions

* update

* update pipeline

* update pipelines

* fix dev/release pipelines for extensions pod

* fix dev pipelines for extensions pod

* fix release pipelines for extensions pod

* fix dev  pipelines for extensions pod

* adding empty include folder for configuring extensions target path

* test

* test

* test

* revert pipeline changes

* revert gitignore changes

* add ext pod binary target for release pipeline

* add pipeline for extensions

* update

* update package.swift

* update latest from branch

* update

* fix

* fix

* update

* try dummy empty file

* test

* update package.swift to use fatalerror

* syntax

* try gitignore revert

* update gitignore

* add -list

* onnxruntime-Package

* update using onnxruntime-Package

* update dev pipeline

* fix dev pipelines

* syntax

* pull extensions/

* update pipelines again

* syntax

* variables

* fix

* fix -r

* update Package.swift

* update Package.swift

* minor update

* address pr comments

* minor updates

* fix

* refine messages

* syntax

* syntax again

* address pr comments partial

* address pr comments

* add .h header file and notes

* minor updates

* syncing objc source files and add code to register custom ops using function pointer

* format

* move to the header for function doc

---------

Co-authored-by: rachguo <rachguo@rachguos-Mini.attlocal.net>
Co-authored-by: rachguo <rachguo@rachguos-Mac-mini.local>

objectivec/cxx_api.h

@@ -11,29 +11,28 @@
 #endif  // defined(__clang__)
 
 // paths are different when building the Swift Package Manager package as the headers come from the iOS pod archive
+// clang-format off
+#define STRINGIFY(x) #x
 #ifdef SPM_BUILD
-#include "onnxruntime/onnxruntime_c_api.h"
-#include "onnxruntime/onnxruntime_cxx_api.h"
-
-#if __has_include("onnxruntime/coreml_provider_factory.h")
-#define ORT_OBJC_API_COREML_EP_AVAILABLE 1
-#include "onnxruntime/coreml_provider_factory.h"
+#define ORT_C_CXX_HEADER_FILE_PATH(x) STRINGIFY(onnxruntime/x)
 #else
-#define ORT_OBJC_API_COREML_EP_AVAILABLE 0
+#define ORT_C_CXX_HEADER_FILE_PATH(x) STRINGIFY(x)
+#endif
+// clang-format on
+
+#if __has_include(ORT_C_CXX_HEADER_FILE_PATH(onnxruntime_training_c_api.h))
+#include ORT_C_CXX_HEADER_FILE_PATH(onnxruntime_training_c_api.h)
+#include ORT_C_CXX_HEADER_FILE_PATH(onnxruntime_training_cxx_api.h)
+#else
+#include ORT_C_CXX_HEADER_FILE_PATH(onnxruntime_c_api.h)
+#include ORT_C_CXX_HEADER_FILE_PATH(onnxruntime_cxx_api.h)
 #endif
 
-#else
-#include "onnxruntime_c_api.h"
-#include "onnxruntime_cxx_api.h"
-
-#if __has_include("coreml_provider_factory.h")
+#if __has_include(ORT_C_CXX_HEADER_FILE_PATH(coreml_provider_factory.h))
 #define ORT_OBJC_API_COREML_EP_AVAILABLE 1
-#include "coreml_provider_factory.h"
+#include ORT_C_CXX_HEADER_FILE_PATH(coreml_provider_factory.h)
 #else
 #define ORT_OBJC_API_COREML_EP_AVAILABLE 0
-
-#endif
-
 #endif
 
 #if defined(__clang__)