by default turn off pch, the effect is minimal and it causes problems in

case RVersion.h is updated and the entire source is not recompiled.


git-svn-id: http://root.cern.ch/svn/root/trunk@21533 27541ba8-7e3a-0410-8455-c3a389f83636

configure

@@ -99,6 +99,7 @@ enable_cint7=no
 enable_gdml=no
 enable_globus=no
 enable_explicitlink=no
+enable_pch=no
 enable_qt=no
 enable_qtgsi=no
 enable_roofit=no