shadow: Implement fgetspent

src/passwd/fgetspent.c

 #include "pwf.h"
+#include <pthread.h>
 
 struct spwd *fgetspent(FILE *f)
 {
-	return 0;
+	static char *line;
+	static struct spwd sp;
+	size_t size = 0;
+	struct spwd *res = 0;
+	int cs;
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+	if (getline(&line, &size, f) >= 0 && __parsespent(line, &sp) >= 0) res = &sp;
+	pthread_setcancelstate(cs, 0);
+	return res;
 }