hygiene, prepare intern globals for re-entrancy

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, expose extra obarray argument for interning funs
hygiene, remove obint inlines from intern.h
hygiene, lose fixed integer beef slots, provide only what we need
minor, turn obint interns into enumerating interns
hygiene, rename vector type in intern.c internally

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, conditionalise on enumerating interns (through ENUM_INTERNS)

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, make obarrays and interning system re-entrant

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
minor, provide ninterns() accessor

Signed-off-by: Sebastian Freundt <freundt@ga-group.nl>
Merge branch 'core/intern'

* core/intern:
  minor, provide ninterns() accessor
  minor, make obarrays and interning system re-entrant
  minor, conditionalise on enumerating interns (through ENUM_INTERNS)
  hygiene, rename vector type in intern.c internally
  minor, turn obint interns into enumerating interns
  hygiene, lose fixed integer beef slots, provide only what we need
  hygiene, remove obint inlines from intern.h
  minor, expose extra obarray argument for interning funs
  hygiene, prepare intern globals for re-entrancy