feat: add Qt 6 support to CMake

Signed-off-by: Sefa Eyeoglu <contact@scrumplex.net>

cmake/QMakeQuery.cmake

@@ -3,7 +3,11 @@ if(__QMAKEQUERY_CMAKE__)
 endif()
 set(__QMAKEQUERY_CMAKE__ TRUE)
 
-get_target_property(QMAKE_EXECUTABLE Qt5::qmake LOCATION)
+if(QT_VERSION_MAJOR EQUAL 5)
+    get_target_property(QMAKE_EXECUTABLE Qt5::qmake LOCATION)
+elseif(QT_VERSION_MAJOR EQUAL 6)
+    get_target_property(QMAKE_EXECUTABLE Qt6::qmake LOCATION)
+endif()
 
 function(QUERY_QMAKE VAR RESULT)
     exec_program(${QMAKE_EXECUTABLE} ARGS "-query ${VAR}" RETURN_VALUE return_code OUTPUT_VARIABLE output )

cmake/QtVersionlessBackport.cmake

@@ -0,0 +1,97 @@
+#=============================================================================
+# Copyright 2005-2011 Kitware, Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#
+# * Redistributions of source code must retain the above copyright
+#   notice, this list of conditions and the following disclaimer.
+#
+# * Redistributions in binary form must reproduce the above copyright
+#   notice, this list of conditions and the following disclaimer in the
+#   documentation and/or other materials provided with the distribution.
+#
+# * Neither the name of Kitware, Inc. nor the names of its
+#   contributors may be used to endorse or promote products derived
+#   from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#=============================================================================
+
+# From Qt5CoreMacros.cmake
+
+function(qt_generate_moc)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_generate_moc(${ARGV})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_generate_moc(${ARGV})
+    endif()
+endfunction()
+
+function(qt_wrap_cpp outfiles)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_wrap_cpp("${outfiles}" ${ARGN})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_wrap_cpp("${outfiles}" ${ARGN})
+    endif()
+    set("${outfiles}" "${${outfiles}}" PARENT_SCOPE)
+endfunction()
+
+function(qt_add_binary_resources)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_add_binary_resources(${ARGV})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_add_binary_resources(${ARGV})
+    endif()
+endfunction()
+
+function(qt_add_resources outfiles)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_add_resources("${outfiles}" ${ARGN})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_add_resources("${outfiles}" ${ARGN})
+    endif()
+    set("${outfiles}" "${${outfiles}}" PARENT_SCOPE)
+endfunction()
+
+function(qt_add_big_resources outfiles)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_add_big_resources(${outfiles} ${ARGN})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_add_big_resources(${outfiles} ${ARGN})
+    endif()
+    set("${outfiles}" "${${outfiles}}" PARENT_SCOPE)
+endfunction()
+
+function(qt_import_plugins)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_import_plugins(${ARGV})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_import_plugins(${ARGV})
+    endif()
+endfunction()
+
+
+# From Qt5WidgetsMacros.cmake
+
+function(qt_wrap_ui outfiles)
+    if(QT_VERSION_MAJOR EQUAL 5)
+        qt5_wrap_ui("${outfiles}" ${ARGN})
+    elseif(QT_VERSION_MAJOR EQUAL 6)
+        qt6_wrap_ui("${outfiles}" ${ARGN})
+    endif()
+    set("${outfiles}" "${${outfiles}}" PARENT_SCOPE)
+endfunction()
+