Cannot compile on Latest OSX

[l0c0luke]

I get the error

driver-gridseed.c:543:3: error: non-void function 'gridseed_pl2303_init' should return a value [-Wreturn-type]

I also get quite a lot of warnings like ...

driver-gridseed.c:383:22: warning: passing 'unsigned char *' to parameter of type 'const char *' converts between pointers to integer types with different sign [-Wpointer-sign]
        else if (strcasecmp(p, "per_chip_stats")==0) {

Have you seen anyone get this working on OSX yet? Ill happily be your guinea pig

[dtbartle]

Pushed a change to fix the compile error.