gdb/darwin-nat.c: Fix template argument for scoped_restore_tmpl

gdb/darwin-nat.c: Fix template argument for scoped_restore_tmpl

This should be the type of startup_with_shell, whose type was changed
from int to bool at commit 80fd28264.

This fixes the build on macOS:

      CXX    darwin-nat.o
    In file included from ../../gdb/darwin-nat.c:22:
    In file included from ../../gdb/top.h:25:
    In file included from ../../gdb/value.h:23:
    In file included from ../../gdb/frame.h:72:
    In file included from ../../gdb/language.h:26:
    In file included from ../../gdb/symtab.h:33:
    ../../gdb/gdbsupport/gdb_optional.h:155:19: error: no matching constructor for initialization of 'scoped_restore_tmpl<int>'
        new (&m_item) T (std::forward<Args>(args)...);
                      ^  ~~~~~~~~~~~~~~~~~~~~~~~~
    ../../gdb/darwin-nat.c:1995:31: note: in instantiation of function template specialization 'gdb::optional<scoped_restore_tmpl<int> >::emplace<bool *, int>' requested here
              restore_startup_with_shell.emplace (&startup_with_shell, 0);
                                         ^
    ../../gdb/gdbsupport/scoped_restore.h:69:3: note: candidate constructor template not viable: no known conversion from 'bool *' to 'int *' for 1st argument
      scoped_restore_tmpl (T *var, T2 value)
      ^
    ../../gdb/gdbsupport/scoped_restore.h:57:3: note: candidate constructor not viable: requires single argument 'var', but 2 arguments were provided
      scoped_restore_tmpl (T *var)
      ^
    ../../gdb/gdbsupport/scoped_restore.h:76:3: note: candidate constructor not viable: requires single argument 'other', but 2 arguments were provided
      scoped_restore_tmpl (const scoped_restore_tmpl<T> &other)
      ^
    1 error generated.

gdb/ChangeLog
2019-12-08  Wataru Ashihara  <wataash@wataash.com>

	* darwin-nat.c (darwin_nat_target::create_inferior): Fix
	template argument for scoped_restore_tmpl from bool to int.

Change-Id: Ia0202efd34dbce69b6af5d035fa55ed89215138a