CI: enable fuzz test build with cmake

[jouho]

Resolved issues:

Currently, fuzz tests are only built with the Make build system. This change allows us to build fuzz tests using CMake as part of our ongoing effort to migrate from Make to CMake. The primary goal of this PR is to replicate the current functionality provided by Make in CMake. Additional improvements to fuzzing are planned and are described in the call-outs section.

Description of changes:

This change enables building fuzz tests with CMake. The commands to build and run fuzz tests:

  cmake . -Bbuild \
          -DCMAKE_PREFIX_PATH=$LIBCRYPTO_ROOT \
          -DS2N_FUZZ_TEST=on
  cmake --build ./build -- -j $(nproc)
  cmake --build build --target run_fuzz 

Detailed description of changes:

CMakeLists.txt

• Added an option to turn on fuzz test mode. This will create build target for fuzz tests, which can be invoked by running cmake --build build --target run_fuzz after compiling

codebuild/bin/s2n_codebuild.sh

• Updated to use the CMake build system instead of Make when the test target is set to "fuzz". Note: There is currently an issue when running this in CI. Related issue: #4633.

codebuild/spec/buildspec_fuzz.yml

• Introduced as an alternative to using s2n_codebuild.sh. This approach ensures that modifications to how fuzz tests are run can be managed through code reviews, avoiding direct edits on CodeBuild (which is what we do now).

tests/fuzz/runFuzzTest.sh

• Limited the scope of the LD_PRELOAD path to prevent interference with external commands, such as mkdir, ensuring it only affects fuzz tests.

utils/s2n_result.c & utils/s2n_result.h

• Addressed a compilation error when compiling function overrides like global_overrides.c, which could not find the definition of s2n_result_is_ok. Including the source resulted in multiple definition errors due to overrides defining their own definitions. This was resolved by inlining the definition of s2n_result_is_ok into s2n_result.h, as part of the optimization process discussed in this PR #4739.

Call-outs:

Waiting for PR #4739 to be merged to fully apply the s2n_result inline change.

There are several follow-up tasks for general fuzzing improvements that needs to be done. The tasks are being tracked at #4748

Testing:

• GeneralFuzzBatch: link to CodeBuild job takes ~1hour to complete

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.