Add symbian4\config tree, to contain the hrh files which are processed by joinsysdef.pl to resolve conditional elements
source,dst,type,pattern,sysdef
http://developer.symbian.org/oss/FCL/sf/os/graphics/,/sf/os/graphics,branch,NewGraphicsArchitecture,layers.sysdef.xml
http://developer.symbian.org/oss/FCL/sf/os/kernelhwsrv/,/sf/os/kernelhwsrv,branch,CompilerCompatibility,layers.sysdef.xml