CLucene erroneously references "/usr/include/CLucene/ext"

Description:

cmake throws an error as a result of CLucene including a non-existent path. The non-existent path is present in /src/core/libclucene-core.pc.cmake line #4:

includedir=${prefix}/include:${prefix}/include/CLucene/ext

The error thrown by cmake is as follows:

CMake Error in CMakeLists.txt:
  Imported target "PkgConfig::CLucene" includes non-existent path

    "/usr/include/CLucene/ext"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

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

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
  provide.



CMake Error in CMakeLists.txt:
  Imported target "PkgConfig::CLucene" includes non-existent path

    "/usr/include/CLucene/ext"

  in its INTERFACE_INCLUDE_DIRECTORIES.  Possible reasons include:

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

  * An install or uninstall procedure did not complete successfully.

  * The installation package was faulty and references files it does not
  provide.



-- Generating done (0.1s)
CMake Generate step failed.  Build files cannot be regenerated correctly.

I have confirmed this is the issue by rebuilding CLucene omitting the erroneous include path, resulting in a successful build without the error. To do this I modified the existing clucene-core-2.3.3.4-pkgconfig.patch so line #11 drops the reference to -I${prefix}/include/CLucene/ext:

+Cflags: -I${prefix}/include -I@LUCENE_SYS_INCLUDES@

Additional info:

• package version(s): clucene 2.3.3.4-15
• link to upstream bug report, if any: The same issue was detailed and patched under Gentoo here: https://bugs.gentoo.org/show_bug.cgi?id=950316 https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=cad74f9d9c05da27156aee3a733eb74fd8cfbe2d

Steps to reproduce:

1. Attempt to build a package requiring CLucene, such as bibletime-git.
2. Build will fail with CMake Error in CMakeLists.txt.
3. Rebuild and install clucene omitting the issue include path.
4. Now retry building bibletime-git (should work).