CMake : Add build directory to include path

Question

I'm looking for the good way to add the build directory (which is different from my source directory, a git repository) to the include path for gcc, in order to have the classic "config.h" file for portability seen during the compilation.

Answer 1

I was looking for

include_directories (${CMAKE_BINARY_DIR})

To add the build directory in case of out-of-source build.

Answer 2

A more modern approach than the selected answer would be to use

set(CMAKE_INCLUDE_CURRENT_DIR ON)

CMAKE_INCLUDE_CURRENT_DIR - Automatically add the current source and build directories to the include path.