Remove an old workaround that was kept around for ABI-compatibility on x86-64 between different LLVM versions. This means LLVM r67588 is required if you want to compile for x86-64, otherwise the backend will assert when you try to return e.g. struct { int i; char c; } from a function. (In particular, this is no longer compatible with LLVM 2.5) It also means that any code returning small structs on x86-64 will probably need to be recompiled in order to be linkable to code compiled with this change.

module vararg1;

import tango.stdc.stdarg;

extern(C) int add(int n, ...)
{
    va_list ap=void;
    va_start(ap, n);
    int r;
    for (int i=0; i<n; i++)
        r += va_arg!(int)(ap);
    va_end(ap);
    return r;
}

void main()
{
    int i = add(4, 1,2,3,4);
    assert(i == 10);
}