[Build] Deprecate export_core (#7028)

Issue: #

### Brief Summary

.github/workflows/scripts/android-build.sh

@@ -18,7 +18,6 @@ python -m pip install -r requirements_dev.txt
 python setup.py clean
 python setup.py build_ext
 cd build
-aarch64-linux-android-strip libtaichi_export_core.so
 aarch64-linux-android-strip libtaichi_c_api.so
 
 chmod -R 777 "$SCCACHE_DIR"

CMakeLists.txt

@@ -196,16 +196,6 @@ endif()
 configure_file(taichi/common/version.h.in ${CMAKE_SOURCE_DIR}/taichi/common/version.h)
 configure_file(taichi/common/commit_hash.h.in ${CMAKE_SOURCE_DIR}/taichi/common/commit_hash.h)
 
-option(TI_EXPORT_CORE "export taichi core" OFF)
-
-if(ANDROID)
-    set(TI_EXPORT_CORE ON)
-endif()
-
-if (TI_EXPORT_CORE)
-  include(cmake/TaichiExportCore.cmake)
-endif()
-
 option(TI_WITH_C_API "build taichi runtime c-api library" OFF)
 
 if (TI_WITH_C_API)

cmake/TaichiCore.cmake

@@ -25,7 +25,6 @@ set(INSTALL_LIB_DIR ${CMAKE_INSTALL_PREFIX}/python/taichi/_lib)
 
 if(ANDROID)
     set(TI_WITH_VULKAN ON)
-    set(TI_EXPORT_CORE ON)
     set(TI_WITH_LLVM OFF)
     set(TI_WITH_METAL OFF)
     set(TI_WITH_CUDA OFF)
@@ -435,8 +434,6 @@ target_link_libraries(taichi_ui PUBLIC ${CORE_LIBRARY_NAME})
 if(TI_WITH_PYTHON)
     message("PYTHON_LIBRARIES: " ${PYTHON_LIBRARIES})
     set(CORE_WITH_PYBIND_LIBRARY_NAME taichi_python)
-    # Cannot compile Python source code with Android, but TI_EXPORT_CORE should be set and
-    # Android should only use the isolated library ignoring those source code.
     if (NOT ANDROID)
         # NO_EXTRAS is required here to avoid llvm symbol error during build
         file(GLOB TAICHI_PYBIND_SOURCE