debug/gdb: 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: don't patch custom dir location]
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Message-Id: <9ea1b5021fc77582867f.1349931197@localhost.localdomain>
PatchWork-Id: 190791

diff -durN gcc-4.4.5.orig/libstdc++-v3/include/c_global/cstdio gcc-4.4.5/libstdc++-v3/include/c_global/cstdio

--- gcc-4.4.5.orig/libstdc++-v3/include/c_global/cstdio	2009-04-10 01:23:07.000000000 +0200

+++ gcc-4.4.5/libstdc++-v3/include/c_global/cstdio	2010-10-09 23:11:27.000000000 +0200

@@ -139,7 +139,7 @@

 _GLIBCXX_END_NAMESPACE

-#if _GLIBCXX_USE_C99

+#if _GLIBCXX_USE_C99 || defined __UCLIBC__

 #undef snprintf

 #undef vfscanf