If you want to disable performance improvement, add this flag -DENABLE_EXTRAS=0
If you want to enable extra logs, add this flag: -DENABLE_EXTRAS=1 -DENABLE_EXTRA_LOGS=1
Totally disable PCH:
-DNOPCH=1
Or one by one:
-DUSE_COREPCH=0
-DUSE_SCRIPTPCH=0
Other options are available here: