add fgetpwent (nonstandard function)

based on patch by Jeremy Huntwork

include/pwd.h

@@ -9,6 +9,10 @@ extern "C" {
 #define __NEED_uid_t
 #define __NEED_gid_t
 
+#ifdef _GNU_SOURCE
+#define __NEED_FILE
+#endif
+
 #include <bits/alltypes.h>
 
 struct passwd
@@ -33,6 +37,7 @@ int getpwnam_r (const char *, struct passwd *, char *, size_t, struct passwd **)
 
 #ifdef _GNU_SOURCE
 char *getpass(const char *);
+struct passwd *fgetpwent(FILE *);
 #endif
 
 #ifdef __cplusplus

src/passwd/fgetpwent.c

+#include "pwf.h"
+
+struct passwd *fgetpwent(FILE *f)
+{
+	static char *line;
+	static struct passwd pw;
+	size_t size=0;
+	return __getpwent_a(f, &pw, &line, &size);
+}