Issue #487

Issue #487

Issue #487

Right now the only thing that it adds to meta_item is an indication of whether
the attribute was declared inside or outside the item, but I expect it will
become more useful.

Issue #487

Issue #487

Issue #487

This is a somewhat odd place to put these checks, but the data tracked
by that pass, and the available functions, make it trivial to do such
a check there.

It was too clunky and specific before. Now returns a vec of dereference specs
instead of a bunch of special-case information. Further accessors extract
the information they need from this vec.

Move the implementation of vec_append from llvm assembly to a regular upcall 

Before, this would cause an assertion failure in trans.

rustc.exe.exe.