Robert P. J. DAY says:

According to Mike Frysinger, this patch hasn't been necessary since
glibc-2.4+, so turf it from glibc patches 2.5 and up. If someone
complains, it can always go back in.

# Compute x86_64-specific values

CT_DoArchValues() {

    # The architecture part of the tuple:

    CT_TARGET_ARCH="${CT_ARCH}"

}