strerror_r used as non-portable format

[Luiz Angelo Daros de Luca]

I got a elfutils-0.178

glibc provides two different signatures for strerror_r. One is GNU-specific and it is not portable.
The other is

       int strerror_r(int errnum, char *buf, size_t buflen);
                   /* XSI-compliant */

       char *strerror_r(int errnum, char *buf, size_t buflen);
                   /* GNU-specific */

man strerror(3) says:

       The XSI-compliant strerror_r() is preferred for portable applications. It returns the error string in the user-supplied buffer buf of length buflen.

musl implements strerror_r as XSI-compliant version while elfutils uses GNU-specific variant.

The solution should not simply ignore strerror_r return value as it would break build when -Werror=unused-result is set.

An alternative is to do something like: https://github.com/luizluca/openwrt/blob/a79698fefdd9dacb84865c870bf75aee978c005d/package/libs/elfutils/patches/100-musl-compat.patch#L51