Revert r289184, we need more configury for Darwin and *BSD.

llvm-svn: 289185

Author: pcc

llvm/lib/Support/raw_ostream.cpp

@@ -598,11 +598,7 @@ void raw_fd_ostream::close() {
 uint64_t raw_fd_ostream::seek(uint64_t off) {
   assert(SupportsSeeking && "Stream does not support seeking!");
   flush();
-#ifdef LLVM_ON_WIN32
-  pos = ::_lseeki64(FD, off, SEEK_SET);
-#else
-  pos = ::lseek64(FD, off, SEEK_SET);
-#endif
+  pos = ::lseek(FD, off, SEEK_SET);
   if (pos == (uint64_t)-1)
     error_detected();
   return pos;