Address more comments

Author: larryliu0820

backends/qualcomm/CMakeLists.txt

@@ -24,7 +24,7 @@ get_filename_component(
 )
 
 # We only download QNN SDK when we build pip wheel for ExecuTorch.
-if(EXECUTORCH_BUILD_PYBIND)
+if(EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY)
   set(_qnn_default_sdk_dir "${CMAKE_CURRENT_BINARY_DIR}/sdk/qnn")
 
   if(EXISTS "${_qnn_default_sdk_dir}" AND EXISTS "${_qnn_default_sdk_dir}/lib")

setup.py

@@ -676,6 +676,8 @@ def run(self):  # noqa C901
             # like `TorchConfig.cmake` that are provided by pip packages.
             f"-DCMAKE_PREFIX_PATH={cmake_prefix_path}",
             f"-DCMAKE_BUILD_TYPE={cmake_build_type}",
+            # Turn on the wheel building option for downstream CMakeLists.txt.
+            f"-DEXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY=ON",
         ]
 
         # Use ClangCL on Windows.

tools/cmake/preset/default.cmake

@@ -288,6 +288,12 @@ define_overridable_option(
   BOOL
   FALSE
 )
+define_overridable_option(
+  EXECUTORCH_BUILD_WHEEL_DEV_USE_ONLY
+  "On if in the wheel building process. Should only be used to guard code that is only needed for building the wheel."
+  BOOL
+  FALSE
+)
 
 # ------------------------------------------------------------------------------
 # Validations