Regenerate dictionaries on header change

[wdconinc]

Few things are more frustrating than spending 4 days trying to debug a phony problem that is caused by out-of-date dictionaries. With increases in development, more frequent changes in headers, and no automatic way of recompiling dictionaries, we're bound to run into more issues (which may not lead to a crash and only manifest in strange results).

[wdconinc]

cmake/modules/FindROOT.cmake causes the following dictionary command in ROOT_GENERATE_DICTIONARY:

add_custom_command(OUTPUT ${dictionary}.cxx ${dictionary}.h
  COMMAND ${ROOTCINT_EXECUTABLE} -cint -f  ${dictionary}.cxx 
          -c ${ARG_OPTIONS} ${includedirs} ${headerfiles} ${linkdefs}
  DEPENDS ${headerfiles} ${linkdefs})

/usr/local/root/pro/bin/rootcint -cint -f  remollDict.cxx -c \
  -I/home/wdconinc/git/remoll_develop/build/include \
  /home/wdconinc/git/remoll_develop/include/remollRunData.hh;/home/wdconinc/git/remoll_develop/include/remollTextFile.hh \
  /home/wdconinc/git/remoll_develop/include/remollLinkDef.h

The semicolon-separated list is what is given to cmake as the dependencies list, and cmake maybe wants a space-separated list?

We call this as:

ROOT_GENERATE_DICTIONARY(
    remollDict                         # path to dictionary to generate
    "include/remollRunData.hh"         # list of classes to process
    "include/remollTextFile.hh"
    LINKDEF "include/remollLinkDef.h"  # ROOT linkDef file
)