binutils/binutils: rename function that build target libraries

Prepare for the incoming build/host/target frontends.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>

 reporter_name="dsreed on freenode/#crosstool-ng"

 reporter_url=""

 reporter_comment="Enables experimental support for VFP/NEON hardware floating point."