-Wpointer-sign: gdb_byte -> char.

This is sort of the opposite of the previous patch.  Places that
manipulate strings or interfaces that return strings are changed to
use char* instead of gdb_byte*.

gdb/
2013-04-19  Pedro Alves  <palves@redhat.com>

	* avr-tdep.c (avr_io_reg_read_command): New local 'bufstr'.  Use
	it to get a string view of the byte buffer.
	* i386-cygwin-tdep.c (core_process_module_section): Change local 'buf'
	type to gdb_byte *.  Adjust.
	* linux-tdep.c (linux_info_proc, linux_find_memory_regions_full):
	Change local to char *.
	* solib-darwin.c (find_program_interpreter): Change return type to
	char *.  Adjust.
	(darwin_solib_get_all_image_info_addr_at_init): Adjust.
	* solib-dsbt.c (enable_break2): Change local 'buf' to char *.
	* solib-frv.c (enable_break2): Change local 'buf' to char *.
	* solib-spu.c (spu_current_sos): Add gdb_byte * cast.
	* solib-svr4.c (find_program_interpreter): Change return type to
	char *.  Adjust.
	(enable_break): Change local 'interp_name' to char *.
	* spu-multiarch.c (spu_xfer_partial): Add cast to 'char *'.
	* spu-tdep.c (spu_pseudo_register_read_spu): Add cast to 'char *'.
	(spu_pseudo_register_write_spu): Use char for string buffer.
	Adjust.
	(info_spu_event_command, info_spu_signal_command): Add casts to
	'char *'.

gdb/solib-dsbt.c

@@ -840,7 +840,7 @@ enable_break2 (void)
   if (interp_sect)
     {
       unsigned int interp_sect_size;
-      gdb_byte *buf;
+      char *buf;
       bfd *tmp_bfd = NULL;
       CORE_ADDR addr;
       gdb_byte addr_buf[TIC6X_PTR_SIZE];