Unbuffer by default on non-CI (#6693)

Author: eddyashton

CMakeLists.txt

@@ -60,9 +60,11 @@ endfunction()
 
 option(PROFILE_TESTS "Profile tests" OFF)
 
-# Add CCF_PYTHON_PRELAUNCH=unbuffer to env when calling cmake to get coloured
-# test output
-set(PYTHON "$ENV{CCF_PYTHON_PRELAUNCH}" python3)
+if("$ENV{CI}" STREQUAL "")
+  set(PYTHON unbuffer python3)
+else()
+  set(PYTHON python3)
+endif()
 
 set(DISTRIBUTE_PERF_TESTS
     ""