gdb/fortran: print function arguments when printing function type

gdb/fortran: print function arguments when printing function type

Before this commit using ptype on a Fortran function will include
information about the functions return type, but not the expected
arguments as it would for C or C++.  After this commit argument types
are included in the ptype output.

For example, before GDB prints:

    (gdb) ptype fun1
    type = integer(kind=4) ()
    (gdb) ptype is_bigger
    type = logical(kind=4) ()

and after GDB prints:

    (gdb) ptype fun1
    type = integer(kind=4) (integer(kind=4))
    (gdb) ptype is_bigger
    type = logical(kind=4) (integer(kind=4), integer(kind=4))

gdb/ChangeLog:

	* f-typeprint.c (f_type_print_varspec_suffix): Handle printing
	function arguments.

gdb/testsuite/ChangeLog:

	* gdb.fortran/ptype-on-functions.exp: New file.
	* gdb.fortran/ptype-on-functions.f90: New file.