Bignumns always exists, step 1.

Always include gmp.h, it always exists now.
Allow character constants of any size
Updated char tests
release number bumped to 8.0.10 by export.pike
release number bumped to 8.0.11 by export.pike
Calendar: Added some more doc.
FSEvents: misplaced ifdef
Standards.URI: Reduce DWIM.

Fixes issues with Roxen.
Fix -Wglobbered warnings.

One of them was actually legitimate.