Encryption dependency issue MbedTLS, building with ESP-idf-v4.1.1

[jackik1410]

Thank you for this example implementation!

I've been trying to develop based on this project structure, but adding any kind of security is turning out to be difficult.
The MbedTLS dependency managed by the components/open62541/CMakeLists.txt doesn't seem to be working as is.

I am using ESP-IDF version 4.1.1 and the current version of open62541 on the master branch (commit: 4c1ffca2).

idf.py build consistently fails with error messages like this:

CMake Error at /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find MbedTLS (missing: MBEDTLS_INCLUDE_DIRS MBEDTLS_LIBRARY
  MBEDX509_LIBRARY MBEDCRYPTO_LIBRARY)

Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  tools/cmake/FindMbedTLS.cmake:35 (find_package_handle_standard_args)
  CMakeLists.txt:593 (find_package)

I have since attempted to link to mbedtls version the esp-idf ships in it's installation directory, as well as directly linking to a local clone of the mbedtls git.

using find_package(MbedTLS) with hints to either variant of mbedtls hasn't worked for me so far, neither set(MbedTLS_DIR ${MY_MBEDTLS_INSTALL_DIR}/cmake) or variations of this.

Considering the deprecation warning for the use of UA_ENABLE_ENCRYPTION with value "ON", I assume that open62541 has since underwent updates and this project doesn't match this new version at the moment.

Is this by chance an issue with open62541, esp-idf or my naive attempts yet?