Fortran: Add ftn, the Cray compiler wrapper, to the default search.

Modules/CMakeDetermineFortranCompiler.cmake

@@ -54,6 +54,7 @@ else()
     if(NOT CMAKE_Fortran_COMPILER_INIT)
       # Known compilers:
       #  f77/f90/f95: generic compiler names
+      #  ftn: Cray fortran compiler wrapper
       #  g77: GNU Fortran 77 compiler
       #  gfortran: putative GNU Fortran 95+ compiler (in progress)
       #  fort77: native F77 compiler under HP-UX (and some older Crays)
@@ -73,6 +74,7 @@ else()
       #  then 77 or older compilers, gnu is always last in the group,
       #  so if you paid for a compiler it is picked by default.
       set(CMAKE_Fortran_COMPILER_LIST
+        ftn
         ifort ifc af95 af90 efc f95 pathf2003 pathf95 pgf95 pgfortran lf95 xlf95
         fort gfortran gfortran-4 g95 f90 pathf90 pgf90 xlf90 epcf90 fort77
         frt pgf77 xlf fl32 af77 g77 f77