Factor out the code to find gcc, and add a command-line option to override the default executable name. This should help cross-compilation by allowing a cross-gcc to be specified from the configuration file instead of only through the CC environment variable.

// bug #191

int[3] a = [0: 0, 2: 42, 1: 1];

void main()
{
  assert(a[0] == 0);
  assert(a[1] == 1); // fails!
  assert(a[2] == 42);
}