fixed includes

Author: fstrozzi

fastool.c

@@ -11,8 +11,10 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 */
 
+#define _POSIX_C_SOURCE 1
 #include <stdio.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <string.h>
 #include "kseq.h"