Proper way to use libwebrtc as a submodule

[aniongithub]

That's built in-source, not as a build/install globally. My .gitmodules is:

    [submodule "libwebrtc"]
    path = libwebrtc
    url = https://github.com/aisouard/libwebrtc.git
    branch = release-58

The intention is to be able to get my source tree and build it all once, with libwebrtc binaries being generated locally in my binary directory.

[qknight]

I assume this is a question "how to use libwebrtc" as a submodule and you did not figure that out yet.

I've asked myself the same question but the solution is not so straight forward:

https://stackoverflow.com/questions/61205068/how-to-rewrite-a-find-package-based-library-into-one-which-can-be-embedded-into

SET(CUSTOM_LIBWEBRTC_INSTALLATION_DIR "" CACHE STRING "Should point to the build/installation directory of libwebrtc (the directory with lib/, include/ and webrtc/)")

if( NOT "${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}" STREQUAL "" )
    message("CUSTOM_LIBWEBRTC_INSTALLATION_DIR = '${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}' so we build with a user-supplied LIBWEBRTC location")

    include_directories(
      ${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}/include/webrtc
      ${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}/include/webrtc/third_party/libyuv/include/
      ${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}/webrtc/src/third_party/abseil-cpp
    )
    add_library(libwebrtc STATIC IMPORTED)
    set_property(TARGET libwebrtc PROPERTY IMPORTED_LOCATION "${CUSTOM_LIBWEBRTC_INSTALLATION_DIR}/lib/libwebrtc.a")
    target_link_libraries(${PROJECT_NAME} libwebrtc)
else ()
    message("CUSTOM_LIBWEBRTC_INSTALLATION_DIR NOT DEFINED -> build with bundled LIBWEBRTC")
    # HACK: In libwebrtc's CMakeLists.txt one has to rename the project(libwebrtcx) and also ExternalProject_Add(libwebrtcx ...) to inject
    #       a build time dependency which will build the library/includes first before they can be used from this CMakeLists.txt
    #       This is also why the libwebrtc is included as a third party library below.
    add_dependencies(${PROJECT_NAME} libwebrtcx)
    add_subdirectory(third-party/libwebrtc)
    include_directories(
      ${CMAKE_BINARY_DIR}/sources/third-party/libwebrtc/include/webrtc
      ${CMAKE_BINARY_DIR}/sources/third-party/libwebrtc/include/webrtc/third_party/libyuv/include/
      ${CMAKE_BINARY_DIR}/sources/third-party/libwebrtc/webrtc/src/third_party/abseil-cpp
    )
    add_library(libwebrtc STATIC IMPORTED)
    # FIXME maybe never build in debug mode
    if(CMAKE_BUILD_TYPE MATCHES DEBUG)
        set_property(TARGET libwebrtc PROPERTY IMPORTED_LOCATION "${CMAKE_BINARY_DIR}/sources/third-party/libwebrtc/webrtc/src/out/Debug/obj/libwebrtc.a")
    else()
        set_property(TARGET libwebrtc PROPERTY IMPORTED_LOCATION "${CMAKE_BINARY_DIR}/sources/third-party/libwebrtc/webrtc/src/out/Release/obj/libwebrtc.a")
    endif()
    target_link_libraries(${PROJECT_NAME} libwebrtc)
endif()

# webrtc specific libraries
target_link_libraries(${PROJECT_NAME} X11 Xcomposite Xdamage Xfixes Xext)