--enable-__cxa_atexit: This option will result in C++ shared libraries and C++ programs that are interoperable with other linux distributions. --enable-clocale=gnu: There is a risk that some people will build ABI incompatible C++ libraries if they didn't install all the glibc localedata. Using --enable-clocale=gnu ensures that the "right thing" is done in all cases. If you don't want to use this option and don't want to build all the locales, then at least make sure you installed the de_DE locale with Glibc, since that's the specific locale GCC will check for to determine which locale mode to use (if de_DE is found, gnu mode is used, which is the corrent one to use).