Fix find_file for Doxylocal and if statement

(cherry picked from commit 747ddcac)
Signed-off-by: Christoph Grüninger <gruenich@dune-project.org>

cmake/modules/DuneDoxygen.cmake

@@ -29,7 +29,7 @@ MACRO (prepare_doxyfile)
   message(STATUS "using ${DOXYSTYLE_FILE} to create doxystyle file")
 
   # check whether module has a Doxylocal file
-  find_file(_DOXYLOCAL PATHS ${CURRENT_SOURCE_DIR} NO_DEFAULT_PATH)
+  find_file(_DOXYLOCAL Doxylocal PATHS ${CMAKE_CURRENT_SOURCE_DIR} NO_DEFAULT_PATH)
 
   if(_DOXYLOCAL)
     set(make_doxyfile_command ${CMAKE_COMMAND} -D DOT_TRUE=${DOT_TRUE} -D DUNEWEB_TRUE=\# -D ProjectName=${ProjectName} -D DUNE_MOD_VERSION=${DUNE_MOD_VERSION} -D DOXYSTYLE=${DOXYSTYLE_FILE}  -D DOXYLOCAL=${CMAKE_CURRENT_SOURCE_DIR}/Doxylocal -D abs_top_srcdir=${CMAKE_SOURCE_DIR} -D srcdir=${CMAKE_CURRENT_SOURCE_DIR} -D top_srcdir=${CMAKE_SOURCE_DIR} -P ${SCRIPT_DIR}/CreateDoxyFile.cmake)

cmake/scripts/CreateDoxyFile.cmake

 #For now we just support appending Doxyfile and Doxylocal
 FILE(READ ${DOXYSTYLE} file_contents)
 FILE(WRITE Doxyfile.in ${file_contents})
-if(_DOXYLOCAL)
+if(DOXYLOCAL)
   FILE(READ ${DOXYLOCAL} file_contents)
 endif()
 FILE(APPEND Doxyfile.in ${file_contents})