Add ARM EABI aliases and remove functions that are also provided by our libc.

Add ARM EABI aliases and remove functions that are also provided by our libc.
This allows linking code compiled by clang with the gcc compiler driver
and makes sure we always use the softfloat implementation in libc.  The
libc softfloat implementation is preferred over the one in libgcc as it
implements rounding modes and floating point exceptions.

ok patrick@