ClangConfig.cmake in bad directory

[Braedy Kuzma]

Description: Ubuntu 16.04.2 LTS
Release: 16.04

clang-4.0:
  Installed: 1:4.0~svn303688-1~exp1
  Candidate: 1:4.0~svn304242-1~exp1
  Version table:
     1:4.0~svn304242-1~exp1 500
        500 http://apt.llvm.org/xenial llvm-toolchain-xenial-4.0/main amd64 Packages
 *** 1:4.0~svn303688-1~exp1 100
        100 /var/lib/dpkg/status

First, I want to note that my clang-4.0 is from llvm's package and not this package that I'm linked to, but in my (limited) understanding I feel like this error is going to occur both ways. Please correct me if I'm wrong.

ClangConfig.cmake is installed in `/usr/share/llvm-4.0/cmake/ClangConfig.cmake` which is not by default searched by cmake and needs to be remedied by adding a PATHS option to the typical find_package command (i.e. `find_package(Clang REQUIRED CONFIG PATHS "/usr/share/llvm-4.0/cmake/")`). The /usr directory isn't listed in any of the list of directories searched here https://cmake.org/cmake/help/v3.8/command/find_package.html, so this choice seems a little odd to me.

Having remedied this by adding the option another error occurs with the final line of ClangConfig.cmake where it attempts to `include(${CLANG_CMAKE_DIR}/ClangTargets.cmake")`. This fails because earlier CLANG_MAKE_DIR is set through `set(CLANG_CMAKE_DIR "${CLANG_INSTALL_PREFIX}/lib/cmake/clang")` where CLANG_INSTALL_PREFIX has been resolved earlier to be `/usr`. The file `/usr/lib/cmake/clang/ClangMakeTargets.cmake` actually exists at `/usr/share/llvm-4.0/cmake/ClangTargets.cmake`.

My first guess is that it was built in one directory and moved here since the file seems to be a templated file like this https://github.com/llvm-mirror/clang/blob/master/cmake/modules/ClangConfig.cmake.in that gets built by this file https://github.com/llvm-mirror/clang/blob/master/cmake/modules/CMakeLists.txt#L22.

[Braedy Kuzma (puckmaster-84)]

I believe this issue duplicates this: https://groups.google.com/forum/#!topic/linux.debian.bugs.dist/g2S4E-QvmWA

[Launchpad Janitor (janitor)]

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