Hello,

In the next release of TF-PSA-Crypto 1.1.0 and Mbed TLS 4.1.0, we have made significant changes to code that detects features that are not part of C99 proper. The changes are mainly:

• Uniformization of POSIX/Unix feature detection macros.
• Assume a C99-compliant printf (dropping hacks for ancient MSVC and forcing compliant printf on MinGW).
• Expansion of “static assert” in C99 when an official C11 static_assert isn't available.

We believe the new code to be standards-compliant, however it may break the build on some platforms that are not strictly POSIX compliant or cause some new compiler warnings.

If you use TF-PSA-Crypto or Mbed TLS on a “less mainstream” Unix-like platform, or with a compiler that isn't GCC or Clang, and the break builds for you, please open a pull request with the necessary fixes (probably in core/tf_psa_crypto_platform_requirements.h, core/tf_psa_crypto_common.h, or library/mbedtls_platform_requirements.h).

We have also made some minor changes in the Mbed TLS 3.6 long-time support branch. They are significantly less expansive, but may affect platforms that are mostly Linux-like but are not Linux or are using an unusual libc.

Best regards,

-- 
Gilles Peskine
TF-PSA-Crypto and Mbed TLS developer