@JeffBezanson I think this broke my Windows build;
```
$ cd ui
$ make DEFAULT_REPL=basic XC_HOST=x86_64-w64-mingw32
    CC ui/repl.o
repl.c: In function 'parse_opts':
repl.c:56:9: error: initializer element is not constant
         { "code-coverage", no_argument,       &jl_compileropts.code_coverage, 1 },
         ^
repl.c:56:9: error: (near initialization for 'longopts[6].flag')
make: *** [repl.o] Error 1
```

I'm guessing this is because the cross-compiler is running in some C mode that "normal" native compiles don't?  Is there a simple fix we can take to ensure this doesn't happen even in strict C modes?