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

fusl/src/stdio/tempnam.c

+#include <stdio.h>
+#include <fcntl.h>
+#include <errno.h>
+#include <sys/stat.h>
+#include <limits.h>
+#include <string.h>
+#include "syscall.h"
+
+#define MAXTRIES 100
+
+char *__randname(char *);
+
+char *tempnam(const char *dir, const char *pfx)
+{
+        char s[PATH_MAX];
+        size_t l, dl, pl;
+        int try;
+        int r;
+
+        if (!dir) dir = P_tmpdir;
+        if (!pfx) pfx = "temp";
+
+        dl = strlen(dir);
+        pl = strlen(pfx);
+        l = dl + 1 + pl + 1 + 6;
+
+        if (l >= PATH_MAX) {
+                errno = ENAMETOOLONG;
+                return 0;
+        }
+
+        memcpy(s, dir, dl);
+        s[dl] = '/';
+        memcpy(s+dl+1, pfx, pl);
+        s[dl+1+pl] = '_';
+        s[l] = 0;
+
+        for (try=0; try<MAXTRIES; try++) {
+                __randname(s+l-6);
+#ifdef SYS_lstat
+                r = __syscall(SYS_lstat, s, &(struct stat){0});
+#else
+                r = __syscall(SYS_fstatat, AT_FDCWD, s,
+                        &(struct stat){0}, AT_SYMLINK_NOFOLLOW);
+#endif
+                if (r == -ENOENT) return strdup(s);
+        }
+        return 0;
+}