Cray 11.0 adds support for preprocessing with output written to a
specified file (instead of always next to the source). Use it to
enable Cray Fortran with the Ninja generator.
Patch-by: James Elliott
Fixes: #20731
Define `CMAKE_Fortran_SUBMODULE_{SEP,EXT}` for the Cray Fortran
compiler. Use an empty separator to tell CMake that this compiler does
not use the enclosing module name as a prefix on submodule files.
Issue: #18925
Define a "Fortran_FORMAT" target and source file property. Initialize
the target property from a "CMAKE_Fortran_FORMAT" variable. Interpret
values "FIXED" and "FREE" to indicate the source file format. Append
corresponding flags to the compiler command line.
The Cray Fortran compiler needs "-em" to enable module output and also
"-J." to place the .mod files in the current working directory (instead
of next to the .o file).
