Hi,

I believe I found a memory leak in your code.

In the file: /src/env/putenv.c

In the function: int __putenv(char *s, size_t l, char *r);

The variable `static char **oldenv` is passed to a free in line 29:
`free(oldenv);`.
The variable is a 2d pointer and therefore all contents within it should be
freed.
By freeing only oldenv all the lines of `__environ` are lost.

Possible hotfix:
```
for (int j = 0; oldenv[j]; ++j) free(oldenv[j]);
free(oldenv);
```

Thank you for your support and dedication,
Luca