libc/newlib: Add CUSTOM version and CUSTOM_LOCATION config options and GetCustom

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

Signed-off-by: "David Holsgrove" <david.holsgrove@xilinx.com>
[yann.morin.1998@free.fr: fix indentation]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <d02252752d4dc5e68ae3.1349931202@localhost.localdomain>
PatchWork-Id: 190795

--- a/bfd/elf32-arm.c

+++ b/bfd/elf32-arm.c

@@ -12408,7 +12408,8 @@ elf32_arm_check_relocs (bfd *abfd, struc

 	  /* If the symbol is a function that doesn't bind locally,

 	     this relocation will need a PLT entry.  */

-	  root_plt->refcount += 1;

+	  if (root_plt->refcount != -1)

+	    root_plt->refcount += 1;

 	  if (!call_reloc_p)

 	    arm_plt->noncall_refcount++;