Test using sherpa-onnx as a cmake subproject (#1961)

+cmake_minimum_required(VERSION 3.13 FATAL_ERROR)
+
+project(use-of-sherpa-onnx-as-a-sub-project)
+
+if(NOT EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/sherpa-onnx/setup.py")
+  message(FATAL_ERROR "Please download the source code of sherpa-onnx and put it inside this directory")
+endif()
+
+set(CMAKE_ARCHIVE_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib")
+set(CMAKE_LIBRARY_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/lib")
+set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "${CMAKE_BINARY_DIR}/bin")
+
+include_directories(./sherpa-onnx)
+add_subdirectory(./sherpa-onnx)
+
+add_executable(main main.cc)
+target_link_libraries(main sherpa-onnx-core)

+#include "sherpa-onnx/csrc/offline-recognizer.h"
+#include "sherpa-onnx/csrc/parse-options.h"
+
+int main(int32_t argc, char *argv[]) {
+  sherpa_onnx::ParseOptions po("help info");
+  sherpa_onnx::OfflineRecognizerConfig config;
+  config.Register(&po);
+  po.PrintUsage();
+  return 0;
+}

+name: as_cmake_sub_project
+
+on:
+  push:
+    branches:
+      - master
+  pull_request:
+    branches:
+      - master
+
+  workflow_dispatch:
+
+concurrency:
+  group: as-cmake-sub-project-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  as_cmake_sub_project:
+    name: ${{ matrix.os }} shared ${{ matrix.shared_lib }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        shared_lib: [ON, OFF]
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: ccache
+        uses: hendrikmuhs/ccache-action@v1.2
+        with:
+          key: ${{ matrix.os }}-${{ matrix.shared_lib }}-cmake-sub-project
+
+      - name: Display PWD
+        shell: bash
+        run: |
+          echo "pwd: $PWD"
+          ls -lh
+          du -h -d1 .
+
+      - name: Build
+        shell: bash
+        run: |
+          mv .github/scripts/as-cmake-sub-project ..
+          cd ../as-cmake-sub-project
+          ln -s $PWD/../sherpa-onnx .
+          mkdir build
+          cd build
+          cmake -DBUILD_SHARED_LIBS=${{ matrix.shared_lib }} ..
+          make -j2 main
+
+      - name: Test
+        shell: bash
+        run: |
+          cd ../as-cmake-sub-project
+
+          cd build
+          ls -lh lib
+          echo "----"
+          ls -lh bin
+
+          readelf -d ./bin/main
+          ./bin/main

@@ -322,8 +322,8 @@ if(WIN32 AND MSVC)
   add_compile_options("$<$<CXX_COMPILER_ID:MSVC>:/utf-8>")
 endif()
 
-list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake/Modules)
-list(APPEND CMAKE_MODULE_PATH ${CMAKE_SOURCE_DIR}/cmake)
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules)
+list(APPEND CMAKE_MODULE_PATH ${CMAKE_CURRENT_SOURCE_DIR}/cmake)
 
 if(SHERPA_ONNX_ENABLE_WASM)
   # Enable it for debugging in case there is something wrong.