Improve build process for Linux

drivers/Linux/Arduino.h

@@ -51,6 +51,7 @@ char *ltoa(long value, char* result, int base);
 char *ultoa(long num, char *str, int radix);
 char *utoa(int num, char *str, int radix);
 char *dtostrf(float f, int width, int decimals, char *result);
+void delay(unsigned int millis);
 
 #ifdef __cplusplus
 	}

drivers/Linux/compatibility.cpp

@@ -1,4 +1,5 @@
 #include <stdio.h>
+#include <time.h>
 #include "Arduino.h"
 
 /**
@@ -175,3 +176,12 @@ char *dtostrf(float f, int width, int decimals, char *result)
 	sprintf(result,"%*.*f", width, decimals, f);
 	return result;
 }
+
+void delay(unsigned int millis)
+{
+    struct timespec sleeper;
+    
+    sleeper.tv_sec  = (time_t)(millis / 1000);
+    sleeper.tv_nsec = (long)(millis % 1000) * 1000000;
+    nanosleep(&sleeper, NULL);
+}