Fix the problems exposed by the callingconv1.d test case. The first was that unless otherwise specified, inputs are assumed to be in registers even if they specify a "matching output" that's in memory. While testing that fix, I also ran into a bug causing the generated "matching output" for any input was always the first one instead of the correct one.

module tangotests.ina1;

import tango.stdc.stdio;

void main()
{
    int alder;
    printf("Hvor gammel er du?\n");
    scanf("%d", &alder);
    printf("om 10 år er du %d\n", alder + 10);
}