cmake: Prefix ROOT_GENERATE_DICTIONARY with FAIRROOT

Fixes: #1221

Our `ROOT_GENERATE_DICTIONARY` conflicts with a CMake macro
by ROOT.

So rename ours to `FAIRROOT_GENERATE_DICTIONARY`.

CHANGELOG.md

@@ -32,6 +32,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
     flexible local code by users.
   * Replace with a local template, `configure_file`, and `execute_process()`
   * In your template consider using `source @FairRoot_BINDIR/FairRootConfig.sh`
+* Renamed our `ROOT_GENERATE_DICTIONARY` to `FAIRROOT_GENERATE_DICTIONARY`.
+  (It's not used in many places anyway, it seems.)
 
 ### Deprecations
 

cmake/modules/ROOTMacros.cmake

@@ -43,9 +43,9 @@ Find_Program(ROOT_CINT_EXECUTABLE
   )
 
 
-macro(ROOT_GENERATE_DICTIONARY)
+macro(FAIRROOT_GENERATE_DICTIONARY)
   if(${ARGC} GREATER 0)
-    message(FATAL_ERROR "ROOT_GENERATE_DICTIONARY has no args")
+    message(FATAL_ERROR "FAIRROOT_GENERATE_DICTIONARY has no args")
   endif()
   if(NOT FAIRROOTPATH)
     message(FATAL_ERROR "Do not call from inside FairRoot")
@@ -206,7 +206,7 @@ Macro(GENERATE_LIBRARY)
     Else( IS_ABSOLUTE ${LINKDEF})
       Set(Int_LINKDEF ${CMAKE_CURRENT_SOURCE_DIR}/${LINKDEF})
     EndIf( IS_ABSOLUTE ${LINKDEF})
-    ROOT_GENERATE_DICTIONARY()
+    FAIRROOT_GENERATE_DICTIONARY()
     SET(Int_SRCS ${Int_SRCS} ${DICTIONARY})
     SET_SOURCE_FILES_PROPERTIES(${DICTIONARY}
        PROPERTIES COMPILE_FLAGS "-Wno-old-style-cast"