move some rsp bits into rsp-low.h

This moves various low-level remote serial protocol bits into
common/rsp-low.[ch].

This is as close to a pure move as possible.  There are some
redundancies remaining but those will be dealt with in a subsequent
patch.

Note that the two variants of remote_escape_output disagreed on the
treatment of "*".  On the theory that quoting cannot hurt but the
absence possibly can, I chose the gdbserver variant to be the
canonical one.

2014-02-12  Tom Tromey  <tromey@redhat.com>

	* tracepoint.c: Include rsp-low.h.
	* remote.h (hex2bin, bin2hex, unpack_varlen_hex): Don't declare.
	* remote.c: Include rsp-low.h.
	(hexchars, ishex, unpack_varlen_hex, pack_nibble, pack_hex_byte)
	(fromhex, hex2bin, tohex, bin2hex, remote_escape_output)
	(remote_unescape_input): Move to common/rsp-low.c.
	* common/rsp-low.h: New file.
	* common/rsp-low.c: New file.
	* Makefile.in (SFILES): Add common/rsp-low.c.
	(HFILES_NO_SRCDIR): Add common/rsp-low.h.
	(COMMON_OBS): Add rsp-low.o.
	(rsp-low.o): New target.

2014-02-12  Tom Tromey  <tromey@redhat.com>

	* tracepoint.c: Include rsp-low.h.
	* server.c: Include rsp-low.h.
	* remote-utils.h (convert_ascii_to_int, convert_int_to_ascii)
	(unhexify, hexify, remote_escape_output, unpack_varlen_hex): Don't
	declare.
	* remote-utils.c: Include rsp-low.h.
	(fromhex, hexchars, ishex, unhexify, tohex, hexify)
	(remote_escape_output, remote_unescape_input, unpack_varlen_hex)
	(convert_int_to_ascii, convert_ascii_to_int): Move to
	common/rsp-low.c.
	* regcache.c: Include rsp-low.h.
	* ax.c: Include rsp-low.h.
	* Makefile.in (SFILES): Add common/rsp-low.c.
	(OBS): Add rsp-low.o.
	(rsp-low.o): New target.

gdb/tracepoint.c

@@ -55,6 +55,7 @@
 #include "probe.h"
 #include "ctf.h"
 #include "filestuff.h"
+#include "rsp-low.h"
 
 /* readline include files */
 #include "readline/readline.h"