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

fusl/src/passwd/getpw_r.c

+#include "pwf.h"
+#include <pthread.h>
+
+#define FIX(x) (pw->pw_##x = pw->pw_##x-line+buf)
+
+static int getpw_r(const char *name, uid_t uid, struct passwd *pw, char *buf, size_t size, struct passwd **res)
+{
+        char *line = 0;
+        size_t len = 0;
+        int rv = 0;
+        int cs;
+
+        pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+
+        rv = __getpw_a(name, uid, pw, &line, &len, res);
+        if (*res && size < len) {
+                *res = 0;
+                rv = ERANGE;
+        }
+        if (*res) {
+                memcpy(buf, line, len);
+                FIX(name);
+                FIX(passwd);
+                FIX(gecos);
+                FIX(dir);
+                FIX(shell);
+        }
+        free(line);
+        pthread_setcancelstate(cs, 0);
+        return rv;
+}
+
+int getpwnam_r(const char *name, struct passwd *pw, char *buf, size_t size, struct passwd **res)
+{
+        return getpw_r(name, 0, pw, buf, size, res);
+}
+
+int getpwuid_r(uid_t uid, struct passwd *pw, char *buf, size_t size, struct passwd **res)
+{
+        return getpw_r(0, uid, pw, buf, size, res);
+}