binutils/elf2flt: Add CUSTOM version, CUSTOM_LOCATION config options, GetCustom

CUSTOM_LOCATION config options only presented in menuconfig if component
CUSTOM version selected.

Change elf2flt CT_ELF2FLT_VERSION from 'head' to 'cvs' if cvs selected in config

Also remove hardcoded 'cvs-' from elf2flt component name, used in CT_Extract,
CT_Patch and as the CT_SRC_DIR location for the configure stage.

Signed-off-by: "David Holsgrove" <david.holsgrove@xilinx.com>
[yann.morin.1998@free.fr: fix indentation, don't patch custom dir location]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <288db3721a37844defa5.1349931196@localhost.localdomain>
PatchWork-Id: 190789

 alpha does not have a __NR_creat

 http://bugs.gentoo.org/227275

 http://sourceware.org/bugzilla/show_bug.cgi?id=6650

 diff -durN glibc-2.10.1.orig/sysdeps/unix/sysv/linux/wordsize-64/creat64.c glibc-2.10.1/sysdeps/unix/sysv/linux/wordsize-64/creat64.c

 --- glibc-2.10.1.orig/sysdeps/unix/sysv/linux/wordsize-64/creat64.c	2007-11-10 20:34:26.000000000 +0100

 +++ glibc-2.10.1/sysdeps/unix/sysv/linux/wordsize-64/creat64.c	2009-11-13 00:50:51.000000000 +0100

 @@ -1 +1,5 @@

  /* Defined as alias for the syscall.  */

 +#include <sysdep.h>

 +#ifndef __NR_creat

 +#include "../../../../../io/creat64.c"

 +#endif