I already have Xcode command line tools installed. The Mac I'm trying to install the agent on has Mac OS X Server installed (10.11.5) - not sure if that makes a difference. Something is reporting an error about SSL headers during the install, and I never get prompted to put the IP for the allowed host (our NagiosXI instance)
checking for SSL headers... configure: error: Cannot find ssl headers
Subcomponents installation failed - exiting
A-subcomponents appears to have already completed successfully. Moving on to the next step.
Starting NRPE Agent