Apply and persist required esp-idf changes for esp_config.h files

[chris-subtlebytes]

Motivations

Some files in the ESP IDF require local modifications because they don't have sdkconfig options for them.

In my case, I need to enable MBEDTLS_USE_PSA_CRYPTO, which can only be enabled by patching:
components/mbedtls/port/include/mbedtls/esp_config.h:

#define MBEDTLS_USE_PSA_CRYPTO

There's also some broken sdkconfig option combinations that need some local patching for now and eventually upstream fixes. In my case, some TLS1.2 macros still try to compile when the TLS1.2 config is disabled.

As of now, there's no official way to automate patching or persist these changes reliably. If these patches are committed, then the cargo build system will actually erase the changes with a fresh sync of the esp idf remote. The current workaround is to manually apply them and leave the .embuild/espressif/esp-idf/v* repo dirty.

• Would you like to implement this feature? [y/n]

No

Desired behavior

A user can download an esp-idf-sys based repository that requires patches to esp-idf and upon cargo build, it automatically syncs the esp-idf (as it does today, or by explicit syncs as some other open FRs suggest), then applies the required patches on top so that the build is successful.

Alternatives

Additional context