Subject: Remove header expansion logic from module cmake helper.
From: Benda Xu <[email-masked]>
Date: 2019-03-23

Description: ROOT module cmake helper by default expands header inclusion to
absolute path.  In Gentoo, that will capture PORTAGE_TMPDIR resulting in various
runtime bugs. By removing this convolved logic, headers are untouched and become
more predictible for rootcling at runtime.

Typical bug it solves:

  Error in cling::AutoloadingVisitor::InsertIntoAutoloadingState:
    Missing FileEntry for /var/tmp/portage/sci-physics/JSAP-479/work/JSAP-479/DataType/JPSimOutput.hh
    requested to autoload type JPSimTruthTree_t
  Error in cling::AutoloadingVisitor::InsertIntoAutoloadingState:
    Missing FileEntry for /var/tmp/portage/sci-physics/JSAP-479/work/JSAP-479/DataType/JPSimOutput.hh
    requested to autoload type JPSimTriggerInfoTree_t

Forwarded: No need. Gentoo specific.

--- a/cmake/modules/RootNewMacros.cmake	2019-01-23 16:23:37.000000000 +0800
+++ b/cmake/modules/RootNewMacros.cmake	2019-02-25 00:18:04.000000000 +0800
@@ -250,14 +250,7 @@ function(ROOT_GENERATE_DICTIONARY dictio
       list(APPEND headerfiles ${fp})
       list(APPEND _list_of_header_dependencies ${fp})
     else()
-      find_file(headerFile ${fp} HINTS ${localinclude} ${incdirs} NO_DEFAULT_PATH)
-      find_file(headerFile ${fp} NO_SYSTEM_ENVIRONMENT_PATH)
-      if(headerFile)
-        list(APPEND headerfiles ${headerFile})
-        list(APPEND _list_of_header_dependencies ${headerFile})
-      else()
-        list(APPEND headerfiles ${fp})
-      endif()
+      list(APPEND headerfiles ${fp})
       unset(headerFile CACHE)
     endif()
   endforeach()