[cpp] package called hx fails to compile when scriptable is defined

[Aidan63]

As the title says, if you have a package named hx it will fail to compile when scriptable is defined, but only if the hx package is not root.

package foo.hx;

class Foo {
    public function new() {}
}

import foo.hx.Foo;

function main() {
    trace(new Foo());
}

The above results in the following errors on 4.3.x and nightlies (just a small snippet since there is a lot...)

Error: Foo.cpp
./src/foo/hx/Foo.cpp(46): error C2039: 'Object': is not a member of 'foo::hx'
./src/foo/hx/Foo.cpp(11): note: see declaration of 'foo::hx'
./src/foo/hx/Foo.cpp(46): error C2039: 'Class': is not a member of 'foo::hx'
./src/foo/hx/Foo.cpp(11): note: see declaration of 'foo::hx'
./src/foo/hx/Foo.cpp(46): error C3646: '__GetClass': unknown override specifier
./src/foo/hx/Foo.cpp(46): error C2059: syntax error: '('
./src/foo/hx/Foo.cpp(46): error C2334: unexpected token(s) preceding '{'; skipping apparent function body
./src/foo/hx/Foo.cpp(46): error C2039: 'MarkContext': is not a member of 'foo::hx'
./src/foo/hx/Foo.cpp(11): note: see declaration of 'foo::hx'
./src/foo/hx/Foo.cpp(46): error C2061: syntax error: identifier 'MarkContext'
./src/foo/hx/Foo.cpp(46): error C2039: 'VisitContext': is not a member of 'foo::hx'
./src/foo/hx/Foo.cpp(11): note: see declaration of 'foo::hx'
./src/foo/hx/Foo.cpp(46): error C2061: syntax error: identifier 'VisitContext'
./src/foo/hx/Foo.cpp(47): error C2039: 'Val': is not a member of 'foo::hx'
./src/foo/hx/Foo.cpp(11): note: see declaration of 'foo::hx'
./src/foo/hx/Foo.cpp(47): error C3646: '__Field': unknown override specifier
./src/foo/hx/Foo.cpp(47): error C2059: syntax error: '('

Issue seems to be that some of the C++ cppia macros aren't prefixing hx namespaces with :: so its relatively looking into our non root hx namespace, not the root hx namespace which hxcpp defines a lot of stuff in.

I can think of two possible fixes, add "hx" to the list of reserved keywords in gencpp so it gets remapped, or update the hxcpp macros so :: is prefixed. Maybe both?