[cmake] `add_subdirectory` support

[Challanger524]

Thank you library creators for protecting peoples minds from Microsoft C interfaces!

But why every 3rd library with CMakeLists.txt can't setup a sane project inclusion!?
It is was not hard to create one for this library.

# Setup: odbc-cpp-wrapper (C++ Wrapper for ODBC) #
if(MINGW)
  set(ODBC_INCLUDE_DIR "" CACHE PATH "[MinGW] prevent '../Windows Kits/..' inclusion from VS dev env")
endif()
find_package(ODBC REQUIRED)
file(GLOB_RECURSE ODBCCPP_SOURCE_FILES_ "${CMAKE_SOURCE_DIR}/deps/odbc-cpp-wrapper/src/*.cpp")
add_library               (odbccpp STATIC ${ODBCCPP_SOURCE_FILES_})
target_include_directories(odbccpp SYSTEM PUBLIC  "${CMAKE_SOURCE_DIR}/deps/odbc-cpp-wrapper/src")
target_compile_definitions(odbccpp        PUBLIC  ODBC_STATIC)
target_link_libraries     (odbccpp        PUBLIC  ODBC::ODBC)
set_target_properties     (odbccpp PROPERTIES CXX_STANDARD 11 CXX_STANDARD_REQUIRED ON)

target_link_libraries(${PROJECT_NAME} odbccpp)

Should I try to contribute to project's CMakeLists.txt?

[stefanuhrig]

Dear @Challanger524,

Thanks for your proposal.

We did not use globbing as CMake recommends not to use it (https://cmake.org/cmake/help/latest/command/file.html#filesystem).

We also have a doc subdirectory that generates Doxygen documentation. This is missing in your simplified CMakeLists.txt.

[Challanger524]

Not forcing to use globbing nor doxygen ditching, just telling that most good libs support easy CMake build inclusion.
It is actually a sign of good project sources layout that allows to glob them easily.

Nearest example library: https://github.com/nanodbc/nanodbc

# Setup: nanodbc (C++ wrapper for the native C ODBC API) #
add_subdirectory("deps/nanodbc")
target_link_libraries(${PROJECT_NAME} nanodbc)

[stefanuhrig]

Oh, I might have misunderstood.

So, you'd like to make it more convenient to consume this library in its non-compiled form from another CMake project?

Proposals are welcome.