Upgrade dynasm

To commit: cb886b58176dc5cd969f512d1a633f06d7120941
Mon Sep 22 13:44:28 2014 +0200
Updates to DynASM support.

The Makefile now explicitly checks, using the C compiler, for supported
processors. A compiler that understands the GCC option -dM is required
for the detection to work.

Both DynASM and the built in GNU Lightning will only be compiled if
a supported CPU is found.

I addition with the update of the DynASM assembler it's no longer
necessary to have a distinct C file just to put the #include lines
in so the compile itself is a little simpler.