Remove 'unwind' instruction.

The unwind instruction is gone in LLVM 3.1.
condition-to-string should never return #f.

It was handled gracefully in print-pretty-name, but not in
default-last-handler, which then tried to concatenate(#f, "\n") and
failed.

I rather changed the GF to return always a <string> and the default
implementation on <condition> returns the string which was used in
print-pretty-name.
Merge pull request #230 from hannesm/fix-condition-to-string

condition-to-string should never return #f.
Stack allocate Bind_exit_frame rather than via GC.

This more closely matches what HARP does.
Specify the type, avoid implicit int warning.
free_tlv_vector should free what is passed in.
Merge pull request #231 from waywardmonkeys/fix-free-tlv-vector

free_tlv_vector should free what is passed in.
Prefer clang as the C compiler where it is available.

* configure.ac: Search for clang before gcc or cc.
ignore exit code of cp and rm
do not chown
do not patch README, reformulate README for the more general case
Merge pull request #232 from hannesm/fix-makefile

ignore exit code of cp and rm for certain directories
Remove most of the remaining ppc-linux references.
Remove unused code from core-harp. Not built.
Remove buffalo-collector.
Remove no-weakness collector & support.
Remove collector.c.malloc.

This isn't used, probably doesn't compile and hasn't been updated
to keep up with collector.c.
Remove NO_LEAF_OBJECT flag in MPS support.

We still keep flags for finer-grained control over leaf objects.
Remove commented out primitive_alloc_internal.
Remove unused check_runtime_thread_library_uses_segment_register.
Remove SunOS relic.