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>

 # SPARC specific config options

 ## select ARCH_SUPPORTS_32

 ## select ARCH_SUPPORTS_64

 ## select ARCH_DEFAULT_32

 ## select ARCH_USE_MMU

 ## select ARCH_SUPPORT_CPU

 ## select ARCH_SUPPORT_TUNE

 ##

 ## help The SUN SPARC architecture, as defined by:

 ## help     32 bit: http://www.sparc.org/standards/V8.pdf

 ## help     64 bit: http://www.sparc.org/standards/SPARCV9.pdf