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 classes11;
extern(C) int printf(char*, ...);

void main()
{
    static class C
    {
        void func()
        {
            printf("Hello world\n");
        }
    }

    scope c = new C;
    c.func();
}