monobuild vs usual build ccache hits

It's interesting that the difference between a usual build (-) and a monobuild (+) is not so big. To be seen if this can be improved (e.g. once https://github.com/ccache/ccache/issues/597 is closed)

@@ -5,7 +5,7 @@ ii
 ### cc_name
 g++-11.1.0-e80bf-2.36.1-a9696
 ### object file
-GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
+Gaudi/GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
 === DIRECT MODE ===
 ### result version
 1
@@ -66,13 +66,13 @@ GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
 ### arg
 -DJSON_USE_IMPLICIT_CONVERSIONS=1
 ### arg
--I../GaudiKernel/include
+-I../../Gaudi/GaudiKernel/include
 ### arg
 -I/cvmfs/lhcb.cern.ch/lib/lcg/releases/vectorclass/2.01.02-cdfdb/x86_64-centos7-gcc11-opt
 ### arg
 -Iinclude
 ### arg
--I../GaudiPluginService/include
+-I../../Gaudi/GaudiPluginService/include
 ### arg
 -isystem
 ### arg
@@ -108,11 +108,11 @@ GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
 ### arg
 -MT
 ### arg
-GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
+Gaudi/GaudiKernel/CMakeFiles/GaudiKernel.dir/src/Lib/Application.cpp.o
 ### arg
 -MF
 ### inputfile
-../GaudiKernel/src/Lib/Application.cpp
+../../Gaudi/GaudiKernel/src/Lib/Application.cpp
 ### sourcecode
 /***********************************************************************************\
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