cmake/cpack root dictionary issue fixed.

In order that package assembly works, the code needs to be relocatble
and any hints linking it to the original source need to be absent.
The changes here do exactely this. For rootcling the '-inlineInputHeader'
option is needed, otherwise the dictionary wants to load the header
file from the source destination which of course will fail when installing
the package on a machine without the source.

src/external/MusrRoot/CMakeLists.txt

@@ -1,8 +1,14 @@
 # - TMusrRunHeader library ----------------------------------------------------
 
 #--- generate necessary dictionaries ------------------------------------------
+set(MUSRROOT_INC ${CMAKE_SOURCE_DIR}/src/external/MusrRoot)
+set(PREFIX_INC ${CMAKE_INSTALL_PREFIX}/include)
+
 root_generate_dictionary(
-  TMusrRunHeaderDict TMusrRunHeader.h LINKDEF TMusrRunHeaderLinkDef.h
+  TMusrRunHeaderDict 
+  -I${MUSRROOT_INC} -I${PREFIX_INC} TMusrRunHeader.h 
+  LINKDEF TMusrRunHeaderLinkDef.h
+  OPTIONS -inlineInputHeader
   MODULE TMusrRunHeader
 )