[svn r378] Make some errors fatal to prevent segfaults. Error instead of assert on missing label. Fixes: nocompile/ finally_02, 03, 07, 08 goto_16_A, 16_B, 12, 13, 14

module bug8;

void main()
{
    s = newS();
}

S* s;

struct S
{
    int i;
}

S* newS()
{
    auto tmp = new S;
    tmp.i = 4;
    return tmp;
}