include stdinit for arc4random() as pointed out by Jan-Benedict Glaw

include/stdlib.h

@@ -846,6 +846,7 @@ extern int getloadavg (double __loadavg[], int __nelem)
 #endif
 
 #ifdef __UCLIBC_HAS_ARC4RANDOM__
+#include <stdint.h>
 extern u_int32_t arc4random(void);
 extern void arc4random_stir(void);
 extern void arc4random_addrandom(unsigned char *, int);