fix warnings

comedi_calibrate/save_cal.c

@@ -28,6 +28,7 @@ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 #include <stdlib.h>
 #include <assert.h>
 #include <time.h>
+#include <string.h>
 
 #include <comedilib.h>
 

demo/sv.c

@@ -17,6 +17,7 @@
 #include <errno.h>
 #include <getopt.h>
 #include <ctype.h>
+#include <stdlib.h>
 #include "examples.h"
 
 comedi_t *device;