MacFeatures:  Remove OS X warning-silencing dummy

This was only necessary with Apple's gcc, and since we don't compile the
project on OS X anymore, it's now superfluous.
Vectoria:  Silence warnings on newer Apple linkers
iota:  Fix dummy symbol for newer Apple toolchains

Later Apple toolchains got smarter about being annoying.
relix:  Silence "has no symbols" warning
Nitrogen:  Remove effectively empty corpus files

The clang compiler is stripping the static initializers, leaving nothing
(and generating "has no symbols" warnings).
Nitrogen:  Silence "has no symbols" on OS X 10.8
Merge branch 'has-no-symbols'