fix static linking

[sangeet2020]

Hi,

This PR is in reference to the issue: #1541

The current cmake logic does not handle the case where ONNX runtime is pre-installed and static linking is used.

The proposed solution modifies the sherpa-onnx/csrc/CMakeLists.txt file.

if((BUILD_SHARED_LIBS OR SHERPA_ONNX_USE_PRE_INSTALLED_ONNXRUNTIME_IF_AVAILABLE) AND NOT DEFINED onnxruntime_lib_files)
  target_link_libraries(sherpa-onnx-core onnxruntime)
else()
  target_link_libraries(sherpa-onnx-core ${onnxruntime_lib_files})

The modified conditioning allows linking to the pre-installed ONNX Runtime when BUILD_SHARED_LIBS is True or when SHERPA_ONNX_USE_PRE_INSTALLED_ONNXRUNTIME_IF_AVAILABLE is set. This prevents build failures caused by missing onnxruntime_lib_files in static builds.

Thanks

[csukuangfj]

Thank you for your contribution!