I was previously maintaining an mbedTLS fork for classic/Carbon Mac OS (<a href="https://github.com/bslabs/mbedtls">https://github.com/bslabs/mbedtls</a>) for use with libssh2, they were still keeping C89 compatibility at the time which was helpful.<p>Newer versions of CodeWarrior do support C99, but I can't remember if Pro 6 (the last version with a 68k toolchain) does. My go-to was Pro 8, since it's Carbonized you can run it natively on OS X (PPC or under Rosetta 1). It's possible to take the Pro 6 68k tools and use them in Pro 8 as well: <a href="https://github.com/macssh/macssh/wiki/Using-CWPro6's-68k-toolchain-with-CWPro8" rel="nofollow">https://github.com/macssh/macssh/wiki/Using-CWPro6's-68k-too...</a>