add CPPFLAGS and CXX to compile PPL

[potuz]

in SVN20090705-x86_64-Multilib section 10.14 ppl will fail to build unless adding the right flags

CPPFLAGS=-fexceptions CC="gcc -isystem /usr/include ${BUILD32}" \

CXX="g++ -isystem /usr/include ${BUILD32}" \ LDFLAGS="-Wl,-rpath-link,/lib ${BUILD32}" \

./configure --prefix=/usr --host=${CLFS_TARGET32} --enable-shared \ --with-libgmp-prefix=/usr --with-libgmpxx-prefix=/usr

otherwise it will complain about not finding the right GMP