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

fusl/include/mntent.h

+#ifndef _MNTENT_H
+#define _MNTENT_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define __NEED_FILE
+#include <bits/alltypes.h>
+
+#define MOUNTED "/etc/mtab"
+
+#define MNTTYPE_IGNORE  "ignore"
+#define MNTTYPE_NFS     "nfs"
+#define MNTTYPE_SWAP    "swap"
+#define MNTOPT_DEFAULTS "defaults"
+#define MNTOPT_RO       "ro"
+#define MNTOPT_RW       "rw"
+#define MNTOPT_SUID     "suid"
+#define MNTOPT_NOSUID   "nosuid"
+#define MNTOPT_NOAUTO   "noauto"
+
+struct mntent
+{
+        char *mnt_fsname;
+        char *mnt_dir;
+        char *mnt_type;
+        char *mnt_opts;
+        int mnt_freq;
+        int mnt_passno;
+};
+
+FILE *setmntent(const char *, const char *);
+int endmntent(FILE *);
+struct mntent *getmntent(FILE *);
+struct mntent *getmntent_r(FILE *, struct mntent *, char *, int);
+int addmntent(FILE *, const struct mntent *);
+char *hasmntopt(const struct mntent *, const char *);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif