libc++-dev:amd64 3.9.1-3 expects /usr/include/xlocale.h to be installed

[Andrew Paxie]

Environment

Test program on Artful Aardvark 17.10

$ which clang++-5.0
/usr/bin/clang++-5.0

$ clang++-5.0 --version
clang version 5.0.0-3 (tags/RELEASE_500/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin

$ dpkg --status libc++-dev
Package: libc++-dev
Status: install ok installed
Priority: extra
Section: libdevel
Installed-Size: 4180
Maintainer: Ubuntu Developers <email address hidden>
Architecture: amd64
Multi-Arch: same
Source: libc++
Version: 3.9.1-3
Provides: libstdc++-dev
Depends: libc++1 (= 3.9.1-3), libc++-helpers
Description: LLVM C++ Standard library (development files)
 libc++ is a new implementation of the C++ standard library, targeting C++11.
 .
 Features and Goals
 .
   * Correctness as defined by the C++11 standard.
   * Fast execution.
   * Minimal memory use.
   * Fast compile times.
   * ABI compatibility with gcc's libstdc++ for some low-level features such
     as exception objects, rtti and memory allocation.
   * Extensive unit tests.
Original-Maintainer: LLVM Packaging Team <email address hidden>
Homepage: http://libcxx.llvm.org/

Test case that fails

$ clang++-5.0 -stdlib=libc++ -c -x c++ - <<EOF
#include <locale>
EOF

In file included from <stdin>:1:
In file included from /usr/include/c++/v1/locale:182:
/usr/include/c++/v1/__locale:39:11: fatal error: 'xlocale.h' file not found
# include <xlocale.h>
          ^~~~~~~~~~~
1 error generated.

Test case that succeeds

$ clang++-5.0 -c -x c++ - <<EOF
#include <locale>
EOF

Supposed cause

As explained in
https://sourceware.org/ml/libc-alpha/2017-08/msg00010.html
the header file `xlocale.h` has been removed from libc6-dev in release 2.26.

Further information

`/usr/include/xlocale.h` was a file installed with package
`libc6-dev:amd64 (2.24-9ubuntu2)`
on Zesty Zapus.

Package `libc6-dev:amd64 (2.26-0ubuntu2)` no longer provides it.

Also fails to compile with g++ (all versions) configured to use libc++ instead of libstdc++-v3
and all other versions of clang++.

[Andrew Paxie (andrewpaxie)]

Workaround

$ cd /usr/include
$ sudo ln -s locale.h xlocale.h

[Andrew Paxie (andrewpaxie)]

Fixed in libc++ 5.0, but this is not in any repository for artful.

Since libc++-dev 3.9.1-3 is in the universe repository for artful,
it is unreasonable to expect a fix.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.