Add C++20 RAII wrapper around wlroots 0.20 + scenefx

Wraps wlroots' C ABI behind owning types (Display, Backend, Compositor,
Output, XdgShell/Toplevel, Seat/Cursor/Keyboard, Scene/Node/Tree) with
wl_signal -> std::function callbacks. Links the scenefx effect engine and
ships a wlr::fx animation helper. Includes a runnable tinywl-style compositor
and a scene/blur demo.

License: AGPL-3.0-only.

CMakeLists.txt

@@ -0,0 +1,38 @@
+cmake_minimum_required(VERSION 3.16)
+project(wlrootspp VERSION 0.1.0 LANGUAGES C CXX)
+
+set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_POSITION_INDEPENDENT_CODE ON)
+
+if(NOT CMAKE_BUILD_TYPE)
+  set(CMAKE_BUILD_TYPE Release)
+endif()
+
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(WLROOTS REQUIRED IMPORTED_TARGET wlroots-0.20)
+pkg_check_modules(SCENEFX REQUIRED IMPORTED_TARGET scenefx-0.5)
+pkg_check_modules(WAYLAND_SERVER REQUIRED IMPORTED_TARGET wayland-server)
+pkg_check_modules(XKBCOMMON REQUIRED IMPORTED_TARGET xkbcommon)
+pkg_check_modules(PIXMAN REQUIRED IMPORTED_TARGET pixman-1)
+
+file(GLOB_RECURSE WLROOTSPP_SOURCES CONFIGURE_DEPENDS
+  "${CMAKE_CURRENT_SOURCE_DIR}/src/*.cpp")
+file(GLOB_RECURSE WLROOTSPP_HEADERS CONFIGURE_DEPENDS
+  "${CMAKE_CURRENT_SOURCE_DIR}/include/*.hpp")
+
+add_library(wlrootspp ${WLROOTSPP_SOURCES} ${WLROOTSPP_HEADERS})
+target_include_directories(wlrootspp PUBLIC
+  "${CMAKE_CURRENT_SOURCE_DIR}/include")
+target_compile_definitions(wlrootspp PUBLIC WLR_USE_UNSTABLE)
+target_link_libraries(wlrootspp PUBLIC
+  PkgConfig::SCENEFX
+  PkgConfig::WLROOTS
+  PkgConfig::WAYLAND_SERVER
+  PkgConfig::XKBCOMMON
+  PkgConfig::PIXMAN)
+set_target_properties(wlrootspp PROPERTIES
+  CXX_VISIBILITY_PRESET hidden
+  VISIBILITY_INLINES_HIDDEN YES)
+
+add_subdirectory(examples)