complibs/ppl: fix 0.11-0.11.2 to compile with --disable-shared

PPL 0.11 (through 0.11.2) had a small bug where it still tried to build
and test its Java interface even when shared libraries are disabled.
Since that's exactly what ct-ng does, it explodes.

This is the patch from the PPL authors (see final link below).

More information can be found in these messages/threads:

Anthony's initial report and analysis with Yann:
http://www.cygwin.com/ml/crossgcc/2011-05/msg00046.html

Ron Flory hit the same problem:
http://www.cygwin.com/ml/crossgcc/2011-05/msg00054.html

Anthony's report to the ppl-devel list:
http://www.cs.unipr.it/pipermail/ppl-devel/2011-May/017450.html

Roberto's reply with a link to the fix in the PPL git repo:
http://www.cs.unipr.it/pipermail/ppl-devel/2011-May/017455.html

Signed-Off-By: Anthony Foiani <anthony.foiani@gmail.com>

# Options specific to crosstool-NG acting as a backend

config IS_A_BACKEND

    string

    option env="CT_IS_A_BACKEND"

config BACKEND

    bool

    default y if IS_A_BACKEND =  "y" || IS_A_BACKEND =  "Y"

    default n if IS_A_BACKEND != "y" && IS_A_BACKEND != "Y"

config BACKEND_ARCH

    string

    option env="CT_BACKEND_ARCH"

config BACKEND_KERNEL

    string

    option env="CT_BACKEND_KERNEL"

config BACKEND_LIBC

    string

    option env="CT_BACKEND_LIBC"