fstat64 is missing on other DragonFly, NetBSD, OpenBSD

Modern operating systems don't need to implement transitional
extensions for large file support.

include/spdlog/details/os-inl.h

@@ -230,7 +230,7 @@ SPDLOG_INLINE size_t filesize(FILE *f)
 #else // unix
     int fd = fileno(f);
 // 64 bits(but not in osx or cygwin, where fstat64 is deprecated)
-#if !defined(__FreeBSD__) && !defined(__APPLE__) && (defined(__x86_64__) || defined(__ppc64__)) && !defined(__CYGWIN__)
+#if (defined(__linux__) || defined(__sun) || defined(_AIX)) && (defined(__LP64__) || defined(_LP64))
     struct stat64 st;
     if (::fstat64(fd, &st) == 0)
     {