Add support for Qt6 building using CMake

This commit fixes build of the appplication using Qt6 (fixed all upstreams
I needed). Tested scenarios (locally):

- Debian Qt5
- Windows Qt6 (Using MinGW)

I will assume that Debian Qt6 will work, and Qt6/5 MSVC will work. If
not - the CI will find it (lol).

Next steps:
 - Finish windows installer
 - Finish OS bundle
 - Revert back to ninja?
 - Document how to use CPM cache
 - Document how to handle a scenario in which the user has Qt5 and Qt6
installed. I am unsure how this works at all.

CMakeLists.txt

@@ -10,6 +10,10 @@ set(BUILD_BINARY OFF)
 set(USE_BUILD_SHARED_LIBS CACHE BOOL OFF)
 set(BUILD_STATICCACHE OFF)
 
+# Qt single app... is being petty
+find_package(QT NAMES Qt6 Qt5 COMPONENTS Core REQUIRED)
+set(QT_DEFAULT_MAJOR_VERSION ${QT_VERSION_MAJOR})
+
 # setup singleapplication - we want the GUI application, not console
 set(QAPPLICATION_CLASS QApplication CACHE STRING "Inheritance class for SingleApplication")
 
@@ -37,25 +41,26 @@ CPMAddPackage("gh:itay-grudev/SingleApplication#v3.3.4")
 
 # this a a repack of the 8426d9b4d4df1da3c5b2d759e509ae1c50a86667 upstream version with a cmake file
 CPMAddPackage("gh:elcuco/lua#9f06e8ad5b562d71c10fb38e6213c2a07465191a")
-#include(lua.cmake)
 
 # this a a repack of the upstream#52820d5 with a cmake file (upstream does
 # not support building the library, but only unit tests)
-CPMAddPackage("gh:elcuco/editorconfig-core-qt#ffd7d12657fb543a480b5c924cd450c31d107c72")
+CPMAddPackage("gh:elcuco/editorconfig-core-qt#d3d0573066a60cdf73537cfd89e6d90f843daea3")
 
 # this a a repack of the upstream#62e0ce7 with a cmake file
-CPMAddPackage("gh:elcuco/QSimpleUpdater#3407c2d257cc2c1758f864df7aa8657addc5e73f")
+CPMAddPackage("gh:elcuco/QSimpleUpdater#dfbbd8db78cf3c40df5fb3ee9b5a75cd50cae185")
 
 # this a a repack of the upstream#f85a8baec6f401d481341ead87f39d9fe9d284ec with a cmake file
-CPMAddPackage("gh:elcuco/scintilla-code#27dca0231d437db3c1c1aedf8afd243d1854ee6c")
+CPMAddPackage("gh:elcuco/scintilla-code#dd6c3c7ff6d56e24afe69716835e19c4d55db3c9")
 
 # TODO - should we backport this to a stable release?
 # this a a repack of the upstream#0bd13d84b3fef7a72553ab95c43d0d4c9677f70f with a cmake file
 CPMAddPackage("gh:elcuco/lexilla#270fb410dd7518736141c9c9c84880b938d957a7")
 
-# Instead of the two above, you can use a moving branch. Both track
-# upstream `master`. Seem to compile and work.
+# Instead of the repos above, you can use a moving branch. All track
+# upstream `master`.
+#CPMAddPackage("gh:elcuco/editorconfig-core-qt#cmake-support")
 #CPMAddPackage("gh:elcuco/scintilla-code#cmake-support")
+#CPMAddPackage("gh:elcuco/QSimpleUpdater#cmake-support")
 #CPMAddPackage("gh:elcuco/lexilla#cmake-support")
 
 add_subdirectory(src/NotepadNext)

src/NotepadNext/CMakeLists.txt

@@ -2,7 +2,14 @@ set(CMAKE_AUTOMOC ON)
 set(CMAKE_AUTORCC ON)
 set(CMAKE_AUTOUIC ON)
 
-find_package(Qt5 COMPONENTS Widgets PrintSupport REQUIRED)
+find_package(QT NAMES Qt6 Qt5 COMPONENTS Core Core Gui Network Widgets PrintSupport REQUIRED)
+find_package(Qt${QT_VERSION_MAJOR} COMPONENTS Core Gui Network Widgets PrintSupport)
+
+# TODO: why do I need to add print support also here?
+if (Qt6_FOUND)
+    find_package(Qt6 REQUIRED COMPONENTS Core5Compat PrintSupport)
+endif()
+
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
 add_executable(NotepadNext
@@ -115,7 +122,9 @@ add_executable(NotepadNext
     scripts.qrc
 )
 
-target_link_libraries(NotepadNext Qt5::Widgets Qt5::PrintSupport
+# TODO: why do I need to add print support also here?
+target_link_libraries(NotepadNext ${QT_LIBRARIES}
+    Qt::PrintSupport
     libuchardet_static
     lua
     LuaBridge
@@ -126,11 +135,23 @@ target_link_libraries(NotepadNext Qt5::Widgets Qt5::PrintSupport
     scintilla-qt-edit
     lexzilla
 )
+
+if (Qt6_FOUND)
+    target_link_libraries(NotepadNext Qt6::Core5Compat)
+endif()
+
+if(UNIX AND NOT APPLE)
+    # TODO: For some reason - this library slips the linking part.
+    target_link_libraries(NotepadNext xcb)
+endif()
+
 target_include_directories(NotepadNext PRIVATE decorators dialogs docks widgets src)
 target_compile_definitions(NotepadNext PRIVATE APP_VERSION="0.5.0")
 target_compile_definitions(NotepadNext PRIVATE APP_COPYRIGHT="Copyright 2019-2022 Justin Dailey")
 target_compile_definitions(NotepadNext PRIVATE CMAKE_EXPERIMENTAL)
 
+
+# TODO - this needs to be removed from this file.
 if ("${CMAKE_CXX_COMPILER_ID}" MATCHES "Clang")
     target_compile_options(NotepadNext PRIVATE -Wall -Wextra -pedantic --warn-no-unused-variable -Wformat -Wformat-security)
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")
@@ -142,10 +163,6 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
     target_link_options(NotepadNext PRIVATE /guard:cf)
 endif()
 
-# For some reason - this library slips the linking part.
-if(UNIX AND NOT APPLE)
-	target_link_libraries(NotepadNext xcb)
-endif()
 
 include(GNUInstallDirs)
 install(TARGETS NotepadNext)