[Tutez64]

A script class that declares no constructor, directly over a host class, now gets the constructor Haxe generates for it.

hxcpp hands a cppia class without a new its base's constructor only when that base is a cppia class too (CppiaClassInfo::linkTypes). Haxe's own cppia never relies on that, since it always writes the inherited constructor. The emitter did not, so for class Mid extends HostBase {}:

• new Mid() never ran the host's constructor: every field it sets read null or zero, silently;
• a subclass's super(), explicit or the implicit one an initialiser brings, dereferenced the null constructor while linking (CallMember::linkSuperCall) and ended the process, with or without the JIT.

settleImplicitConstructors now also gives such a class the forwarding constructor it already wrote for a class with member initialisers. Only a class whose direct base is a host class gets one: over a script class, hxcpp's inherited constructor is already right, so no call is added there.

	Before	After
new Mid().made (set by HostBase's constructor)	compiled, null	compiled, host
new Sub(), Sub extends Mid with new() super()	segfault while loading	compiled, host
new Sub(), Sub extends Mid with an initialiser	segfault while loading	compiled, host5

A host base whose constructor shape is unknown refuses the module, as it already did for a class with initialisers; the message no longer mentions initialisers.

Tests

• Three corpus cases, over a new made field on the HostBase fixture, set by its constructor. Without the fix, the first fails in the cppia suite (cppia gave null, interpreter gave host) and the second ends it.
• test/run.sh eval cpp on hxcpp master: 421 / 421 / 454. Conformance columns are unchanged apart from the three new rows, compiled in both cppia columns.
• Flixel sandbox (flixel, openfl, lime, plain, JIT on and off): same modules compiled, same byte counts, same two left interpreted (Playground, Shapes) as the baseline.