Bug#862328: clang-4.0: ClangConfig.cmake is broken by Debian packaging

[Sylvain Joubert]

Package: clang-4.0
Version: 1:4.0.1~+rc1-1
Severity: important

Dear Maintainer,

In the same way as #819072 and preceding issues for LLVMConfig, the Clang CMake
files are not usable with the current packaging in Debian.
While LLVMConfig.cmake can be found without issue, this is not the case for
ClangConfig.cmake

Considering the following CMake script:

cmake_minimum_required(VERSION 3.2)
project(clangconfig)
find_package(Clang REQUIRED)

one gets:

CMake Error at CMakeLists.txt:3 (find_package):
  By not providing "FindClang.cmake" in CMAKE_MODULE_PATH this project has
  asked CMake to find a package configuration file provided by "Clang", but
  CMake did not find one.

  Could not find a package configuration file provided by "Clang" with any of
  the following names:

    ClangConfig.cmake
    clang-config.cmake

  Add the installation prefix of "Clang" to CMAKE_PREFIX_PATH or set
  "Clang_DIR" to a directory containing one of the above files.  If "Clang"
  provides a separate development package or SDK, be sure it has been
  installed.

Additionnally, when explicitly providing Clang_DIR with
/usr/share/llvm-4.0/cmake, one gets:

CMake Error at /usr/share/llvm-4.0/cmake/ClangConfig.cmake:17 (include):
  include could not find load file:

    /usr/lib/cmake/clang/ClangTargets.cmake
Call Stack (most recent call first):
  CMakeLists.txt:3 (find_package)

I'm guessing some paths needs to be updated in order to handle the Debian
repackaging.

Sylvain



-- System Information:
Debian Release: 9.0
  APT prefers testing
  APT policy: (990, 'testing'), (800, 'stable-updates'), (800, 'stable'), (700, 'unstable'), (90, 'experimental')
Architecture: amd64
 (x86_64)

Kernel: Linux 4.9.0-2-amd64 (SMP w/8 CPU cores)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages clang-4.0 depends on:
ii  binutils                 2.28-4
ii  libc6                    2.24-10
ii  libc6-dev                2.24-10
ii  libclang-common-4.0-dev  1:4.0.1~+rc1-1
ii  libclang1-4.0            1:4.0.1~+rc1-1
ii  libgcc-6-dev             6.3.0-16
ii  libgcc1                  1:6.3.0-16
ii  libjsoncpp1              1.7.4-3
ii  libllvm4.0               1:4.0.1~+rc1-1
ii  libobjc-6-dev            6.3.0-16
ii  libstdc++-6-dev          6.3.0-16
ii  libstdc++6               6.3.0-16

Versions of packages clang-4.0 recommends:
ii  llvm-4.0-dev  1:4.0.1~+rc1-1
ii  python        2.7.13-2

Versions of packages clang-4.0 suggests:
pn  clang-4.0-doc  <none>
pn  gnustep        <none>
pn  gnustep-devel  <none>

-- no debconf information