gdb/fortran: Allow for matching symbols with missing scope

gdb/fortran: Allow for matching symbols with missing scope

This commit allows symbol matching within Fortran code without having
to specify all of the symbol's scope.  For example, given this Fortran
code:

    module aaa
    contains
      subroutine foo
        print *, "hello."
      end subroutine foo
    end module aaa

    subroutine foo
      print *, "hello."
    end subroutine foo

    program test
      call foo
    contains
      subroutine foo
        print *, "hello."
      end subroutine foo

      subroutine bar
        use aaa
        call foo
      end subroutine bar
    end program test

The user can now do this:

    (gdb) b foo
    Breakpoint 1 at 0x4006c2: foo. (3 locations)
    (gdb) info breakpoints
    Num     Type           Disp Enb Address            What
    1       breakpoint     keep y   <MULTIPLE>
    1.1                         y   0x00000000004006c2 in aaa::foo at nest.f90:4
    1.2                         y   0x0000000000400730 in foo at nest.f90:9
    1.3                         y   0x00000000004007c3 in test::foo at nest.f90:16

The user asks for a breakpoint on 'foo' and is given a breakpoint on
all three possible 'foo' locations.  The user is, of course, still
able to specify the scope in order to place a single breakpoint on
just one of the foo functions (or use 'break -qualified foo' to break
on just the global foo).

gdb/ChangeLog:

	* f-lang.c (f_language_defn): Use cp_get_symbol_name_matcher and
	cp_search_name_hash.
	* NEWS: Add entry about nested function support.

gdb/testsuite/ChangeLog:

	* gdb.fortran/nested-funcs-2.exp: Run tests with and without the
	nested function prefix.