Crypto library C code converted to C++14 with focus on FIPS and algorithm probing

[kvakvs]

Summary

• This PR is a preparation for solving FIPS 140-3 vs supported algorithms in ssh #9520, done separately from the actual changes to make review easier.
• This PR changes programming language used in lib/crypto from C89 to C++14 and modernizes some code aspects to make it safer and cleaner (research was done to find that this will be supported on oldest systems still used in testing lab)
• The next step (not in this PR): When FIPS mode is enabled, all (cipher, digest, pubkey, mac, etc..) algorithms will be challenged against FIPS requirements and removed from the available list if they are forbidden.

Changes

• Attempted to keep the changes to the minimum and leave most code untouched to allow easier review
• Makefile template updated to use CXX compiler instead of CC
• C files renamed to CPP with compile errors and most non-fatal warnings addressed (such as 'argument/variable can be made const', etc)
• struct and enum in typenames is not necessary. Integer NULL become appropriately typed nullptr
• C-style casts become static_cast (for simple conversions), const_cast (for adding or removing const qualifier), and reinterpret_cast (for incompatible value type changes)
• Arrays used for algorithms now are C++ dynamic arrays, removed related support code, loops now use array iteration for (auto &p: array_name) {}
• Enums and bit flags used for algorithms are now bool-type bitfields
• Include file guards now become #pragma once supported for a very long time by all compilers
• Some macros became constexpr or INLINE functions
• Tested on OpenSSL 1.0.1u, 1.1.1, 3.0.0, 3.4.0 (non-FIPS and, where supported, FIPS)
• No changes in documentation, user-facing API or library behaviors.

[github-actions]

CT Test Results

  2 files   14 suites   4m 41s ⏱️
191 tests 171 ✅  18 💤 2 ❌
479 runs  334 ✅ 143 💤 2 ❌

For more details on these failures, see this check.

Results for commit 55f1a6e.

♻️ This comment has been updated with latest results.

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Artifacts

• Complete CT logs (Download Logs)
• HTML Documentation (Download HTML Docs)
• Windows Installer

// Erlang/OTP Github Action Bot