Add a "fork" of musl as //fusl.

fusl/src/passwd/getpwent.c

+#include "pwf.h"
+
+static FILE *f;
+static char *line;
+static struct passwd pw;
+static size_t size;
+
+void setpwent()
+{
+        if (f) fclose(f);
+        f = 0;
+}
+
+weak_alias(setpwent, endpwent);
+
+struct passwd *getpwent()
+{
+        struct passwd *res;
+        if (!f) f = fopen("/etc/passwd", "rbe");
+        if (!f) return 0;
+        __getpwent_a(f, &pw, &line, &size, &res);
+        return res;
+}
+
+struct passwd *getpwuid(uid_t uid)
+{
+        struct passwd *res;
+        __getpw_a(0, uid, &pw, &line, &size, &res);
+        return res;
+}
+
+struct passwd *getpwnam(const char *name)
+{
+        struct passwd *res;
+        __getpw_a(name, 0, &pw, &line, &size, &res);
+        return res;
+}