toolchain Enable erandom/frandom support in glibc for ssp Enable the glibc-compat addon Configure glibc with --enable-omitfp which lets the build system determine when it is safe to use -fomit-frame-pointer Configure the linuxthreads glibc with --with-_thread if supported by your system. --with-tls is always enabled if supported and is NOT controlled by this switch. So the glibc built will always support TLS binaries. This toggle chooses whether or not glibc itself uses TLS. If you're concerned about backwards compatibility with old binaries, leave this off. Disables building the linuxthreads fallback in glibc ebuilds that support building both linuxthread and nptl Build only the locales specified in /etc/locales.build