gambit

[RUNTIME CHANGES NEEDED FOR v4.9.7] Changed version of runtime using misc/changev

[COMPILER CHANGES NEEDED FOR v4.9.7] Changed version in compiler

Default to 4-tag self-tagging which outperforms 1-tag self-tagging on float intensive benchmarks and the same speed on non-float benchmarks

Fix needless boxing of flonum (noticed in pnpoly in r6rs-fixflo-unsafe setting)

Use presence of operand in fp cache to optimize calls to fixnum? and flonum?