This change fixes the symbol merging in get_symbol_decl to also consider
prototypes. This allows the ability to set user defined attributes on
the prototype of a function, which then get applied to the definition,
if found later in the compilation.
The lowering of UDAs to GCC attributes has been commonized into a single
function called apply_user_attributes.
gcc/d/ChangeLog:
PR d/90136
* d-attribs.cc: Include dmd/attrib.h.
(build_attributes): Redeclare as static.
(apply_user_attributes): New function.
* d-tree.h (class UserAttributeDeclaration): Remove.
(build_attributes): Remove.
(apply_user_attributes): Declare.
(finish_aggregate_type): Remove attrs argument.
* decl.cc (get_symbol_decl): Merge declaration prototypes with
definitions. Use apply_user_attributes.
* modules.cc (layout_moduleinfo_fields): Remove last argument to
finish_aggregate_type.
* typeinfo.cc (layout_classinfo_interfaces): Likewise.
* types.cc (layout_aggregate_members): Likewise.
(finish_aggregate_type): Remove attrs argument.
(TypeVisitor::visit (TypeEnum *)): Use apply_user_attributes.
(TypeVisitor::visit (TypeStruct *)): Remove last argument to
finish_aggregate_type. Use apply_user_attributes.
(TypeVisitor::visit (TypeClass *)): Likewise.
gcc/testsuite/ChangeLog:
PR d/90136
* gdc.dg/pr90136a.d: New test.
* gdc.dg/pr90136b.d: New test.
* gdc.dg/pr90136c.d: New test.
