Fix -Wformat warnings in gnu-nat.c

I've seen some -Wformat warnings when build native gdb for hurd.

../../../git/gdb/gnu-nat.c:2384:8: error: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'vm_address_t' [-Werror=format]
../../../git/gdb/gnu-nat.c:2394:8: error: format '%x' expects argument of type 'unsigned int', but argument 2 has type 'vm_address_t' [-Werror=format]
../../../git/gdb/gnu-nat.c: In function 'steal_exc_port':
../../../git/gdb/gnu-nat.c:2898:5: error: format '%d' expects argument of type 'int', but argument 2 has type 'mach_port_t' [-Werror=format]

in usr/include/mach/port.h, we have:

typedef vm_offset_t mach_port_t;

and in usr/include/mach/machine/vm_types.h, we have:

typedef       unsigned long   vm_offset_t;

so this patch changes '%d' to '%lu' in format string for mach_port_t
variables.

Similarly, in usr/include/mach/std_types.h, we have,

typedef      vm_offset_t     vm_address_t;

this patch also changes '%x' to '%lx' in gnu_write_inferior.

gdb:

2014-02-17  Yao Qi  <yao@codesourcery.com>

	* gnu-nat.c (proc_get_exception_port): Use 'lu' insetad of 'd'
	in format string.
	(proc_steal_exc_port, make_proc, inf_set_pid): Likewise.
	(inf_validate_procs, inf_signal): Likewise.
	(S_exception_raise_request): Likewise.
	(do_mach_notify_dead_name): Likewise.
	(steal_exc_port): Likewise.
	(gnu_read_inferior): Change 'copy_count''s type to
	mach_msg_type_number_t.
	(gnu_write_inferior): Likewise.  Use 'lx' instead of 'x' in
	format string.
Fix -Werror=pointer-sign warnings

../../../git/gdb/gnu-nat.c: In function 'gnu_read_inferior':
../../../git/gdb/gnu-nat.c:2282:3: error: pointer targets in passing argument 5 of 'vm_read' differ in signedness [-Werror=pointer-sign]
In file included from /home/yao/Software/hurd-toolchain/bin/../i686-pc-gnu/libc/usr/include/mach.h:38:0,
                 from ./nm.h:23,
                 from ../../../git/gdb/defs.h:500,
                 from ../../../git/gdb/gnu-nat.c:23:
/home/yao/Software/hurd-toolchain/bin/../i686-pc-gnu/libc/usr/include/mach/mach_interface.h:843:15: note: expected 'mach_msg_type_number_t *' but argument is of type 'int *'
../../../git/gdb/gnu-nat.c: In function 'gnu_write_inferior':
../../../git/gdb/gnu-nat.c:2339:4: error: pointer targets in passing argument 5 of 'vm_read' differ in signedness [-Werror=pointer-sign]
In file included from /home/yao/Software/hurd-toolchain/bin/../i686-pc-gnu/libc/usr/include/mach.h:38:0,
                 from ./nm.h:23,
                 from ../../../git/gdb/defs.h:500,
                 from ../../../git/gdb/gnu-nat.c:23:
/home/yao/Software/hurd-toolchain/bin/../i686-pc-gnu/libc/usr/include/mach/mach_interface.h:843:15: note: expected 'mach_msg_type_number_t *' but argument is of type 'int *'

This patch fixes these warnings.

gdb:

2014-02-17  Yao Qi  <yao@codesourcery.com>

	* gnu-nat.c (gnu_read_inferior): Change 'copy_count' type to
	mach_msg_type_number_t.
	(gnu_write_inferior): Likewise.
Fix missing-prototypes warnings in gnu-nat.c

A recent change (commit 3398af6aa352b0611bc9d66aed72080a876e42d4)
in gnu-nat.c causes the some missing-prototypes warnings,

../../../git/gdb/gnu-nat.c:1864:1: error: no previous prototype for 'S_proc_pid2task_reply' [-Werror=missing-prototypes]
../../../git/gdb/gnu-nat.c:1866:1: error: no previous prototype for 'S_proc_task2pid_reply' [-Werror=missing-prototypes]
../../../git/gdb/gnu-nat.c:1868:1: error: no previous prototype for 'S_proc_task2proc_reply' [-Werror=missing-prototypes]

A new macro ILL_RPC was added recently, which defines some external
functions.  However, they are not declared and GCC complains about this.

This patch is to add the declarations of these external function in
macro ILL_RPC.

gdb:

2014-02-17  Yao Qi  <yao@codesourcery.com>

	* gnu-nat.c (ILL_RPC): Declare defined function.