Resolve OpenSSL 4.0 build issues

[jeredfloyd]

Fedora 45 updates to OpenSSL 4.0, which removes several long-deprecated capabilities and breaks ATS build. Specific issues fixed are lack of const tagging of pointers to immutable structures, and disallowed introspection of ASN1_STRING. Resolves #13427

[JosiahWI]

[approve ci]

[JosiahWI]

@jeredfloyd Could you run the clang-format CMake target?

[jeredfloyd]

@JosiahWI oops; done

[JosiahWI]

../src/tscore/X509HostnameValidator.cc:269:15: error: no matching function for call to 'X509_NAME_get_index_by_NID'
while ((i = X509_NAME_get_index_by_NID(name, NID_commonName, i)) >= 0) {
^~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/include/openssl/x509.h:810:5: note: candidate function not viable: 1st argument ('const X509_NAME *' (aka 'const X509_name_st *')) would lose const qualifier
int X509_NAME_get_index_by_NID(X509_NAME *name, int nid, int lastpos);

Apparently, not all the X509 APIs in older OpenSSL versions take the name as pointer to const. Would it work to use auto or decltype to determine the type of the local variable, so that it automatically assumes the correct type for both APIs? (If this approach is used, there should be a comment explaining why this was done.) That's just one idea; I'm interested in how you recommend to fix it.

[jeredfloyd]

Huh. I can't access the trafficserver CI logs; can you tell me what OS versions / OpenSSL versions are in use on the failing CentOS/Debian/FreeBSD/Ubuntu jobs?

I don't see why decltype wouldn't work, but I don't work much with C++ so I don't want to proffer a strong opinion here.