I just remembered you can do something like this!
```
import std.stdio;
enum FEATURE_A_AVAILABLE()
{
version(FEATURE_A) return true;
else return false;
}
void main()
{
static if (!FEATURE_A_AVAILABLE)
{
writeln("feature A not available");
}
}
```
It's evaluated at compile time, so it's branchless!
