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 complex4;

void main()
{
    cfloat c = 2f + 3fi;
    float r = cast(float)c;
    ifloat i = cast(ifloat)c;
}