remove Chars variant from Obj union.
comment.
update cc.sh warnings.
String, Hash_set, Hash_map defs; use Hash_map for symbol caching.
Hash_map prep; const correctness.
rename run_call_* to type case.
add unused assoc field to Func.
Labeled-args.
ptr() method.
int, sym methods.
bool methods.
xcode now uses default compiler; settings shared using @ options.
data methods.
moved Head definition above Obj.
inlined rc methods.
inlined data methods.
move int0, blank into Obj def.
inlined Obj constructors.
cmpd methods.