Add Don't Care Bit Analysis.
Remove warning

warning: no previous prototype for 'dca_analyze' [-Wmissing-prototypes]
Add optimization: occult_consts

Now we have a simple optimization actually using DCA.
user of analysis must reserve resources

This is safer for resources the user requires itself, since the
information must live longer than the analysis then.
Fix static library creation

Since we have two fp-vrp.o files, the -u argument of ar sometimes (on
rebuilds) missed one. As -u is not necessary anyways, we now include both.
Refactor: better name for former 'fp-vrp' analysis