Add comprehensive C library testsuite

[stephanosio]

Summary

Add a comprehensive C library test suite that:

• tests the functional requirements of all supported C libraries to ensure that the C library meets the Zephyr expectations.
• has common codebase for testing different C libraries (focus on testing standard C features).

Background

We currently have tests/lib/c_lib; but, this test suite is by no means comprehensive and is missing many tests leading to the issues like #51978.

Resources

• picolibc tests
• libc-test from musl
• llvm libc test
• bionic libc test

Tasks

Test Clean-up

• Remove tests/lib/c_lib
  • This is a half-baked test for a very limited subset of the libc.
  • tests/lib/libc, aka. "comprehensive C library test," will replace it in its entirety.
• Remove tests/lib/sprintf
  • There is no reason for a separate sprintf test to exist.
  • This test will be part of the new tests/lib/libc test.
  • Any cbprintf-specific bits, outside the scope of the ISO C standard, ought to be tested by the cbprintf tests.
• Remove tests/lib/time
  • There is no reason for a separate time test to exist.
  • This test will be part of the new tests/lib/libc test.

Test Implementation

• assert.h
• complex.h
• ctype.h
• errno.h
• fenv.h
• float.h
• inttypes.h
• iso646.h
• limits.h
• locale.h
• math.h
• setjmp.h
• signal.h
• stdarg.h
• stdbool.h
• stddef.h
• stdint.h
• stdio.h
• stdlib.h
• string.h
• tgmath.h
• time.h
• wchar.h
• wctype.h

[zephyrbot]

Hi @stephanosio,

This issue, marked as an Enhancement, was opened a while ago and did not get any traction. Please confirm the issue is correctly assigned and re-assign it otherwise.

Please take a moment to review if the issue is still relevant to the project. If it is, please provide feedback and direction on how to move forward. If it is not, has already been addressed, is a duplicate, or is no longer relevant, please close it with a short comment explaining the reason.

Thanks!