NODE_LABELS: the variable defines a list of OS properties. The set values are used by the build scripts to select proper behavior for different OS.
The list should include at least [OS_TYPE], [DISTRO_TYPE], and [DISTRO_VERSION].
Possible values for Linux OS:
[OS_TYPE]: Linux[DISTRO_TYPE]: Ubuntu[DISTRO_VERSION]: Ubuntu-14.04, Ubuntu-16.04Possible values of OSX OS:
[OS_TYPE]: OSX[DISTRO_TYPE]: OSX (can be absent)[DISTRO_VERSION]: OSX-10.11, OSX-10.10, OSX-10.9, OSX-10.8JOB_NAME: optional variable to define type of the job. Depending on the defined job type, the build scripts can perform different tasks.
Possible values:
code-coverage (Linux OS is assumed): build process with code coverage analysislimited-build: only a single build with testsCACHE_DIR: the variable defines a path to folder containing cached files from previous builds, e.g., a compiled version of ndn-cxx library. If not set, /tmp is used.