WITH_CURL off still tries to include curl.h

[jerry-123123]

#cmakedefine01 (in config.h.in) sets WITH_OAUTHBEARER_OIDC as either 0 (when disabled) or 1 (when enabled). The problem is that #ifdef checks if a symbol is defined, not its value. So #ifdef WITH_OAUTHBEARER_OIDC is always true causing curl.h to always be required.

[jerry-123123]

There is an MR that fixes this already: https://github.com/confluentinc/librdkafka/pull/5182

[tillrohrmann]

I would love to get this fixed as well. Either via #5182 or #5136.