by code that checks if it is an ExtensibleAlgType and whether the root attribute and arity are the same

reorder some function arguments,
don't call getBelongingSymbols again in get_nth_belonging_decl

modules_explicit_imports, component_mods and path to functions

specialize functions search_symbol and search_imported_symbol for searching a symbol or belongings of a symbol,
the specialize functions for belongings are search_belonging_symbol and search_imported_symbol_and_belonging,
remove cUndef, implies and stupid_ident

rename function try_children to search_symbol_in_imports,
inline local function continue

add some function types

replace fields icl_import and icl_qualified_imports by icl_imported_instances,
add type GlobalInstanceIndex,
add function collect_imported_instances to module explicitimports,
remove unused Position from si_qualified_explicit

add type GlobalInstanceIndex,
add function collect_imported_instances to module explicitimports,
remove unused Position from si_qualified_explicit

from module checksupport to explicitimports,
make ExplImpInfo abstract and don't export DeclaringModulesSet and DeclarationInfo

[ReferenceCount] usually consists of many RC_Unused,
these lists are replaced by a single ReferenceCountsAllUnused

add types in TC contexts of constructors with dictionaries to the type environment of dynamic types (at runtime).
to fix for example:

:: T = E.a b: A (a -> b) & TC a & TC b

tToDyn :: !T -> Dynamic
tToDyn (A x) = toDyn x

toDyn :: a -> Dynamic | TC a
toDyn a = dynamic a

instead add only one gtpv_subst variable for each sequence of _bind_global_type_pattern calls

we can currently only check if there is an import, not whether it should be a qualified import