Refactor CMake build scripts

1. Use FeatureSummary module to show configuration results.

2. Invert option()/find_package() relationship: instead of
calling find_package(... REQUIRED) when option is set, rely on optional
find package call and PackageName_FOUND variable.

3. Refactor handling options that result in simple preprocessor defines
(actually copy the snippet from libtorrent) so that everything is done
in a single function call.

4. Populate target properties in order to get rid of
include_directories() calls.

src/CMakeLists.txt

@@ -1,40 +1,45 @@
 set(CMAKE_CXX_STANDARD_REQUIRED True)
 set(CMAKE_CXX_STANDARD "11")
-add_definitions(-DBOOST_NO_CXX11_RVALUE_REFERENCES)
 
 include(MacroQbtCompilerSettings)
 qbt_set_compiler_options()
 
-include(MacroLinkQtComponents)
 include(QbtTargetSources)
 
+find_package(Boost ${requiredBoostVersion} REQUIRED)
 find_package(LibtorrentRasterbar REQUIRED)
 
-# Qt
-list(APPEND QBT_QT_COMPONENTS Core Network Xml)
-if (GUI)
-    list (APPEND QBT_QT_COMPONENTS Gui Svg Widgets)
-    if (WIN32)
-        list (APPEND QBT_QT_COMPONENTS WinExtras)
-    endif(WIN32)
-    if (APPLE)
-        list (APPEND QBT_GUI_OPTIONAL_LINK_LIBRARIES objc)
-        list (APPEND QBT_QT_COMPONENTS MacExtras)
-    endif (APPLE)
-endif (GUI)
-if (DBUS)
-    list (APPEND QBT_QT_COMPONENTS DBus)
-endif (DBUS)
-find_package(Qt5 5.5.1 COMPONENTS ${QBT_QT_COMPONENTS} REQUIRED)
+if (Boost_VERSION VERSION_LESS 106000)
+    add_definitions(-DBOOST_NO_CXX11_RVALUE_REFERENCES)
+endif()
 
-if (GUI AND APPLE)
-    # Fix MOC inability to detect macOS. This seems to only affect cmake.
-    # Relevant issue: https://bugreports.qt.io/browse/QTBUG-58325
-    set(CMAKE_AUTOMOC_MOC_OPTIONS ${CMAKE_AUTOMOC_MOC_OPTIONS} -DQ_OS_MAC)
-endif ()
+find_package(Qt5 ${requiredQtVersion} REQUIRED COMPONENTS Core Network Xml)
+find_package(Qt5Widgets ${requiredQtVersion})
+if (Qt5Widgets_FOUND)
+    find_package(Qt5DBus ${requiredQtVersion})
+else()
+    add_definitions(-DDISABLE_GUI)
+endif()
+
+set_package_properties(Qt5Widgets PROPERTIES
+    DESCRIPTION "Set of components for creating classic desktop-style UIs for the Qt5 framework"
+    PURPOSE "Enables qBittorrent GUI. Unneeded for headless configuration."
+    TYPE OPTIONAL
+)
+
+set_package_properties(Qt5DBus PROPERTIES
+    DESCRIPTION "Qt5 module for inter-process communication over the D-Bus protocol"
+    PURPOSE "Enables communication with other system components (e.g. notification service) via D-Bus. "
+    TYPE RECOMMENDED
+)
 
 set(CMAKE_AUTOMOC True)
 list(APPEND CMAKE_AUTORCC_OPTIONS -compress 9 -threshold 5)
+if (APPLE)
+    # Workaround CMake bug (autogen does not pass required parameters to moc)
+    # Relevant issue: https://gitlab.kitware.com/cmake/cmake/issues/18041
+    list(APPEND CMAKE_AUTOMOC_MOC_OPTIONS -DQ_OS_MAC -DQ_OS_DARWIN)
+endif ()
 
 include_directories(${CMAKE_CURRENT_SOURCE_DIR})
 
@@ -43,56 +48,34 @@ add_definitions(-DQT_NO_CAST_TO_ASCII)
 # Efficient construction for QString & QByteArray (Qt >= 4.8)
 add_definitions(-DQT_USE_QSTRINGBUILDER)
 
-if (NOT GUI)
-    add_definitions(-DDISABLE_GUI -DDISABLE_COUNTRIES_RESOLUTION)
-endif (NOT GUI)
-
-if (NOT WEBUI)
-    add_definitions(-DDISABLE_WEBUI)
-endif (NOT WEBUI)
-
-if (STACKTRACE)
-    add_definitions(-DSTACKTRACE)
-endif(STACKTRACE)
-# nogui {
-#     TARGET = qbittorrent-nox
-# } else {
-#     CONFIG(static) {
-#         DEFINES += QBT_STATIC_QT
-#         QTPLUGIN += qico
-#     }
-#     TARGET = qbittorrent
-# }
-
-if (UNIX AND NOT APPLE)
-    add_compile_options(-Wformat -Wformat-security)
-endif ()
-
-if (CMAKE_BUILD_TYPE STREQUAL "Debug")
+if (CMAKE_BUILD_TYPE MATCHES "Debug")
     message(STATUS "Project is built in DEBUG mode.")
-else (CMAKE_BUILD_TYPE STREQUAL "Debug")
+else()
     message(STATUS "Project is built in RELEASE mode.")
     message(STATUS "Disabling debug output.")
     add_definitions(-DQT_NO_DEBUG_OUTPUT)
-endif (CMAKE_BUILD_TYPE STREQUAL "Debug")
-
-set(QBT_USE_GUI ${GUI})
-set(QBT_USE_WEBUI ${WEBUI})
+endif()
 
 configure_file(config.h.cmakein ${CMAKE_CURRENT_BINARY_DIR}/config.h)
 
-if (SYSTEM_QTSINGLEAPPLICATION)
-    find_package(QtSingleApplication REQUIRED)
-else (SYSTEM_QTSINGLEAPPLICATION)
+find_package(QtSingleApplication)
+set_package_properties(QtSingleApplication PROPERTIES
+    URL "https://code.qt.io/cgit/qt-solutions/qt-solutions.git/"
+    DESCRIPTION "Qt library to start applications only once per user"
+    TYPE RECOMMENDED
+    PURPOSE "Use the system qtsingleapplication library or shipped one otherwise"
+)
+
+if (NOT QtSingleApplication_FOUND)
     add_subdirectory(app/qtsingleapplication)
-endif (SYSTEM_QTSINGLEAPPLICATION)
+endif ()
 
 add_subdirectory(app)
 add_subdirectory(base)
 
-if (GUI)
+if (Qt5Widgets_FOUND)
     add_subdirectory(gui)
-endif (GUI)
+endif ()
 
 if (WEBUI)
     add_subdirectory(webui)