[svn r305] Started support for custom class allocators/deallocators. Allocators with more than one argument still need to be fixed. Removed the LLVM stacktrace code from mars.c. Moved the LLVM based default target detection code from mars.c to llvmhelpers.cpp.

module bug44;

pragma(LLVM_internal, "notypeinfo")
struct rgb
{
    long l;
}

void foo()
{
}

rgb test() {
  scope(exit) foo();
  return rgb();
}

void main()
{
    rgb r = test();
}