Make fixepoint.c as a shared library (libfixedpoint.a).

Change-Id: Icc10d6e85f890c432f191233a4d64e09f00be43d
Reviewed-on: http://gerrit.rockbox.org/456
Reviewed-by: Michael Sevakis <jethead71@rockbox.org>
Tested-by: Michael Sevakis <jethead71@rockbox.org>
28 files changed