When building otel module as a part of nginx build system process (via
./configure --add-dynamic-module=nginx-otel/), there is no way to pass
additional options to the cmake invocation, making it impossible link
the module with desired ssl library variant.
With the patch, it's not possible to pass the additional options, e.g.
NGINX_OTEL_ADDITIONAL_OPTS="-DOPENSSL_ROOT_DIR=/usr/lib64/openssl11;/usr/include/openssl11"
./configure --add-dynamic-module=nginx-otel/, and cmake will pick up the
correct ssl variant to link the module with.
