espidf COMPONENT_DIR - cmake

Question

I'm trying to compile a simple Hello_world example using the Smooth component (https://github.com/PerMalmberg/Smooth), and get error: include could not find load file:
../lib/compiler_options.cmake.
It seems that COMPONENT_DIR is not set, but I'm not aware whether/where to set this, or where this should have been set.
I've been staring at this too long, and am not finding the (apparently) obvious problem. Anyone any thoughts?
ERROR
Note: You are using Python 3.8.0. Python 3 support is new, please report any problems you encounter. Search for 'Setting
the Python Interpreter' in the ESP-IDF docs if you want to use Python 2.7.
Checking Python dependencies...
Python requirements from C:\Esp32_tools\esp-idf-v3.3\requirements.txt are satisfied.
Running cmake in directory C:\Temp\esp\testCPP\build
Executing "cmake -G Ninja -DPYTHON_DEPS_CHECKED=1 -DESP_PLATFORM=1 --warn-uninitialized C:\Temp\esp\testCPP"...
Warn about uninitialized values.
-- Building for target esp32
-- ccache will be used for faster builds
CMake Error at C:/Temp/esp/testCPP/externals/smooth/smooth_component/CMakeLists.txt:21 (include):
include could not find load file:
../lib/compiler_options.cmake
Call Stack (most recent call first):
C:/Esp32_tools/esp-idf-v3.3/tools/cmake/scripts/expand_requirements.cmake:107 (include)
C:/Esp32_tools/esp-idf-v3.3/tools/cmake/scripts/expand_requirements.cmake:217 (expand_component_requirements)`
CMake Error at C:/Esp32_tools/esp-idf-v3.3/CMakeLists.txt:39 (message):
Failed to expand component requirements
VERSION
C:\Temp\esp\testCPP>cmake --version
cmake version 3.13.4
CMake suite maintained and supported by Kitware (kitware.com/cmake).
CMakeLists.txt
set(CMAKE_CXX_STANDARD 17)
if(${ESP_PLATFORM})
include($ENV{IDF_PATH}/tools/cmake/project.cmake)
# Include Smooth as a component
set(EXTRA_COMPONENT_DIRS
externals/smooth/smooth_component)
project(name_of_your_project)
else()
# Empty project when not building for ESP (i.e. when loading the project into an IDE with already configured tool chains for native Linux)
endif()```

Answer 1

CMake Error at C:/Esp32_tools/esp-idf-v3.3/CMakeLists.txt:39 (message):
Failed to expand component requirements
You are missing this line in CMakeLists.txt
https://github.com/espressif/esp-idf/blob/master/examples/get-started/hello_world/CMakeLists.txt#L3