In order to upgrade a VortexDX86 custom linux with a gcc 3.2.3
compiler, I´m trying to built the GCC 5.2.0 compiler to support the latest C++ 11 standard.
I
You need a working C++ compiler to build recent releases of GCC, and you don't seem to have that (your GCC 3.2.3 seems to be missing the C++ standard library headers).
I suggest that you use the existing compiler to build GCC 4.7.4 (which can still be built by a C compiler) to get a working C++ compiler. Then use GCC 4.7.4 to build GCC 5.2