Adds explicit alignment information for alloca instructions in general, there's a few cases that still needs to be looked at but this should catch the majority. Fixes ticket #293 .

module mainargs1;

extern(C) int printf(char*,...);

void main(char[][] args)
{
    foreach(v; args)
    {
        printf("%.*s\n", v.length, v.ptr);
    }
}