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.

module bug25;
extern(C) int printf(char*, ...);

void main()
{
    int i = 2;
    delegate {
        i = i*i;
        i += i*i;
    }();
    printf("%d\n", i);
    assert(i == 20);
}