Description of problem:
On musl libc *strerror_r* defined to return int even with _GNU_SOURCE:
```
/* /usr/include/string.h */
#if defined(_POSIX_SOURCE) || defined(_POSIX_C_SOURCE) \
 || defined(_XOPEN_SOURCE) || defined(_GNU_SOURCE) \
 || defined(_BSD_SOURCE)
// ...
int strerror_r (int, char *, size_t);
// ...
```

this causes compilation error:
```
lvmpolld-core.c:56:9: error: incompatible integer to pointer conversion returning 'int' from a
      function with result type 'const char *' [-Wint-conversion]
        return strerror_r(errnum, data->buf, sizeof(data->buf)); /* never returns NULL */
```

Version-Release number of selected component (if applicable):
2.03.14

How reproducible:
Always

Steps to Reproduce:
Try to build on musl libc


Expected results:
Successful build