[clang] [llvm] [lld] [libcxx] [flang] [libc++][streams] P1759R6: Native handles and file streams (PR #76632)

[Mark de Wever via cfe-commits]

================
@@ -85,6 +85,7 @@ endif()
 if (LIBCXX_ENABLE_LOCALIZATION)
   list(APPEND LIBCXX_SOURCES
     include/sso_allocator.h
+    fstream.cpp
----------------
mordante wrote:

```suggestion
    fstream.cpp
    include/sso_allocator.h
```
Let's keep it in alphabetic order.

https://github.com/llvm/llvm-project/pull/76632