cmake llvm detection is broken due to missing dependencies:

The following minimal CMakeLists.txt

project(foo)
find_package(LLVM 16 REQUIRED)

fails with

CMake Error at /usr/lib/llvm-16/lib/cmake/llvm/LLVMExports.cmake:1809 (message):
  The imported target "omptarget" references the file

     "/usr/lib/llvm-16/lib/libomptarget.so.16"

  but this file does not exist.  Possible reasons include:

  * The file was deleted, renamed, or moved to another location.

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and contained

     "/usr/lib/llvm-16/lib/cmake/llvm/LLVMExports.cmake"

  but not all the files it references.

Call Stack (most recent call first):
  /usr/lib/llvm-16/cmake/LLVMConfig.cmake:359 (include)
  CMakeLists.txt:2 (find_package)

We believe that the bug you reported is fixed in the latest version of
llvm-toolchain-16, which is due to be installed in the Debian FTP archive.

A summary of the changes between this version and the previous one is
attached.

Thank you for reporting the bug, which will now be closed.  If you
have further comments please address them to 1033933@bugs.debian.org,
and the maintainer will reopen the bug report if appropriate.

Debian distribution maintenance software
pp.
Gianfranco Costamagna <locutusofborg@debian.org> (supplier of updated llvm-toolchain-16 package)

(This message was generated automatically at their request; if you
believe that there is a problem with it please contact the archive
administrators by mailing ftpmaster@ftp-master.debian.org)
Format: 1.8
Date: Tue, 11 Apr 2023 14:09:36 +0200
Source: llvm-toolchain-16
Built-For-Profiles: noudeb
Architecture: source
Version: 1:16.0.1-1~exp2
Distribution: experimental
Urgency: medium
Maintainer: LLVM Packaging Team <pkg-llvm-team@lists.alioth.debian.org>
Changed-By: Gianfranco Costamagna <locutusofborg@debian.org>
Closes: 1033933
Changes:
 llvm-toolchain-16 (1:16.0.1-1~exp2) experimental; urgency=medium
 .
   [ Sylvestre Ledru ]
   * cherry pick changes from snapshot for sccache
 .
   [ Gianfranco Costamagna ]
   * Use parallel=2 on riscv64
   * Add omptarget again to optional interfaces (Closes: #1033933)
   * Adapt test when llvm is built without Z3 support (error message changed)
Checksums-Sha1:
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 97284c850d6c4e7a003f88117bb14d415a66b14d 164308 llvm-toolchain-16_16.0.1-1~exp2.debian.tar.xz
 d8dda24589eb28f35c86f688e3c5daecf73d169a 11686 llvm-toolchain-16_16.0.1-1~exp2_source.buildinfo
Checksums-Sha256:
 054c6fe3f498c789b21b1856b7e4f437ed8b20d3d535112a62910f6988f8b623 8155 llvm-toolchain-16_16.0.1-1~exp2.dsc
 bc6f2f1935aa2780c2010bad68ee3fa257c5b6ddc049ee09723bef4144386a85 164308 llvm-toolchain-16_16.0.1-1~exp2.debian.tar.xz
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Files:
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 7bc639465302404295d02cb0f34c7a96 164308 devel optional llvm-toolchain-16_16.0.1-1~exp2.debian.tar.xz
 34a0b030fdb467f9e070580267ea6bcc 11686 devel optional llvm-toolchain-16_16.0.1-1~exp2_source.buildinfo
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