Fortran is not a prerequisite for building ROOT

git-svn-id: http://root.cern.ch/svn/root/trunk@41478 27541ba8-7e3a-0410-8455-c3a389f83636

cmake/modules/CheckCompiler.cmake

@@ -4,7 +4,7 @@
 
 #---Enable FORTRAN (unfortunatelly is not nowt possible in all cases)-------------------------------
 if(NOT WIN32 AND NOT CMAKE_GENERATOR STREQUAL Xcode)
-  enable_language(Fortran)
+  enable_language(Fortran OPTIONAL)
 endif()