complibs/ppl: remove unnecessary (and confusing) --enable-cxx configure switch.

PPL does not use the "--enable-cxx" configure switch at all; it's
possibly a cut-and-paste leftover from 'gmp.sh'. (PPL is written in C++
natively, so it doesn't make much sense to have to enable C++; GMP, on
the other hand, is written in C with an optional C++ wrapper.)

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

mainmenu "The crosstool-NG configuration menu"

source "config/backend.in"

source "config/global.in"

source "config/target.in"

source "config/toolchain.in"

source "config/kernel.in"

source "config/binutils.in"

source "config/cc.in"

source "config/libc.in"

source "config/debug.in"

source "config/companion_libs.in"

source "config/companion_tools.in"

source "config/test_suite.in"