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.

struct Vertex {
    uint[1] c;
}

void main() {
    uint[1] c = 0xffffffff;

    auto v = Vertex(c);

    assert(v.c[0] == 0xffffffff);  // fails in LDC
}