cross-compile: comment out sleep().

Reported as unneded:
https://github.com/veox/sgminer/issues/37

When is this true? Which IDEs, Windows/MinGW versions?

compat.h

@@ -47,15 +47,16 @@ static inline int nanosleep(const struct timespec *req, struct timespec *rem)
 }
 #endif
 
-static inline int sleep(unsigned int secs)
-{
-	struct timespec req, rem;
-	req.tv_sec = secs;
-	req.tv_nsec = 0;
-	if (!nanosleep(&req, &rem))
-		return 0;
-	return rem.tv_sec + (rem.tv_nsec ? 1 : 0);
-}
+/* Reported unneded in https://github.com/veox/sgminer/issues/37 */
+/* static inline int sleep(unsigned int secs) */
+/* { */
+/* 	struct timespec req, rem; */
+/* 	req.tv_sec = secs; */
+/* 	req.tv_nsec = 0; */
+/* 	if (!nanosleep(&req, &rem)) */
+/* 		return 0; */
+/* 	return rem.tv_sec + (rem.tv_nsec ? 1 : 0); */
+/* } */
 
 enum {
 	PRIO_PROCESS		= 0,