libc/glibc: configure libc headers with support for 128-bit long double

At the headers install pass, there's no compiler to test for the size
of long double. Help it: we know that the compiler does support 128-bit
long double, in the IBM extended precision.

Kindly pointed out, and explained, by Mike FRYSINGER:
http://sourceware.org/ml/crossgcc/2009-11/msg00040.html
http://sourceware.org/ml/crossgcc/2009-11/msg00057.html

#!/bin/sh

canonicalizedname=$(readlink -nm "${0}")

dirname="$(dirname "${canonicalizedname}")"

basename="$(basename "${canonicalizedname}")"

ld_lib_path="$(dirname "${dirname}")/lib"

case ":${LD_LIBRARY_PATH}:" in

    *":${ld_lib_path}:"*)   ;;

    *)  LD_LIBRARY_PATH="${ld_lib_path}${LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}";;

esac

export LD_LIBRARY_PATH

exec "${dirname}/.${basename}" "$@"