Remove all traces of reg_char.

Remove all traces of reg_char.

	* sysdeps/generic/memcopy.h (reg_char): Delete.
	* debug/strcat_chk.c: Use char, not reg_char.
	* debug/strcpy_chk.c: Likewise.
	* debug/strncat_chk.c: Likewise.
	* debug/strncpy_chk.c: Likewise.
	* string/memchr.c: Likewise.
	* string/memrchr.c: Likewise.
	* string/rawmemchr.c: Likewise.
	* string/strcat.c: Likewise.
	* string/strchr.c: Likewise.
	* string/strchrnul.c: Likewise.
	* string/strcmp.c: Likewise.
	* string/strcpy.c: Likewise.
	* string/strncat.c: Likewise.
	* string/strncmp.c: Likewise.
	* string/strncpy.c: Likewise.