z/OS doesn't support fopen64() functions. Modify the preprocessor directive for z/OS to use fopen() instead.
Reviewed By: #libc, abhina.sreeskantharajan, muiez, ldionne
Differential Revision: https://reviews.llvm.org/D111226
// 2GB.
std::string create_file(fs::path filename_path, uintmax_t size = 0) {
std::string filename = filename_path.string();
-#if defined(__LP64__) || defined(_WIN32)
+#if defined(__LP64__) || defined(_WIN32) || defined(__MVS__)
auto large_file_fopen = fopen;
auto large_file_ftruncate = utils::ftruncate;
using large_file_offset_t = off_t;