incorrect install interface, result the package is not relocatable

[kangsheng89]

xgboost/CMakeLists.txt

Line 206 in 1fa6793

$<INSTALL_INTERFACE:${CMAKE_INSTALL_PREFIX}/include>

This line of INSTALL_INTERFACE is wrong and not relocatable. This will result that INTERFACE_INCLUDE_DIRECTORIES set as hardcoded path based on CMAKE_INSTALL_PREFIX from Build Machine

please refer to this https://cmake.org/cmake/help/latest/manual/cmake-packages.7.html#creating-relocatable-packages

preferable to use as:
$<INSTALL_INTERFACE:$<INSTALL_PREFIX>/include>

[trivialfis]

Thanks for pointing that out @kangsheng89 . Would you like to open a PR for addressing the issue?

[kangsheng89]

@trivialfis please review the changes! Thanks

[trivialfis]

Thanks for the PR!

[kangsheng89]

Welcome!!