engine/tests/Makefile: Don't build/run test_var if C++ not enabled (test_var requires IronBee++).
engine/tests/Makefile: Don't build/run test_var if C++ not enabled (test_var requires IronBee++).

ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee