Difficult to configure Xrootd to use non-builtin openssl

[Axel-Naumann]

Explain what you would like to see improved

In builtins/xrootd/CMakeLists.txt we don't pass any openssl configuration over to Xrootd. This causes inconsistent builds for ROOT and xrootd.

Optional: share how it could be improved

Maybe use

OPENSSL_CRYPTO_LIBRARY
OPENSSL_SSL_LIBRARY
OPENSSL_INCLUDE_DIR

as made available with Xrootd's CMakeLists.txt.

To Reproduce

See https://root-forum.cern.ch/t/building-from-source-root-v6-26-00-failing-with-openssl-on-macos-monterey/49078

[bellenot]

@Axel-Naumann According to the Xrootd README, the only OpenSSL related variable we can pass is OPENSSL_ROOT_DIR. Not sure it would solve this issue...

[dpiparo]

@amadio what's your take on this?

[amadio]

XRootD now uses the standard CMake module to link against OpenSSL. If you configure ROOT correctly, you should be able to just forward the OpenSSL variables to XRootD and it should work. If not, please let me know.

[guitargeek]

Only one line of change needed to close an issue? Let's go:

• [CMake] Forward OPENSSL_ROOT_DIR to builtin xrootd #15697