CMake: Add WinMain support

Change-Id: I85c56555bc47dcf348daeb3435c621529aa2d381
Fixes: QTBUG-75195
Reviewed-by: Cristian Adam <cristian.adam@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

cmake/QtBuild.cmake

@@ -1657,12 +1657,6 @@ function(add_qt_executable name)
     endif()
 
 
-    if(WIN32)
-        # Workaround for not having ported the winmain / qtmain static library
-        # which is always linked in by qmake.
-        set_target_properties("${name}" PROPERTIES WIN32_EXECUTABLE 0)
-    endif()
-
     if(NOT arg_NO_INSTALL)
         qt_install(TARGETS "${name}"
             RUNTIME DESTINATION "${arg_INSTALL_DIRECTORY}"

src/CMakeLists.txt

@@ -54,3 +54,5 @@ if(QT_FEATURE_gui AND QT_FEATURE_widgets)
    add_subdirectory(printsupport)
 endif()
 add_subdirectory(plugins)
+
+add_subdirectory(winmain)

src/winmain/.prev_CMakeLists.txt

@@ -0,0 +1,48 @@
+# Generated from winmain.pro.
+
+#####################################################################
+## qtLibraryTarget$$TARGET$$QT_LIBINFIX Module:
+#####################################################################
+
+add_qt_module(qtLibraryTarget$$TARGET$$QT_LIBINFIX
+    STATIC
+    DEFINES
+        QT_NO_FOREACH
+    PUBLIC_LIBRARIES
+        Qt::Core
+)
+
+#### Keys ignored in scope 1:.:.:winmain.pro:<TRUE>:
+# CONFIG = "static"
+# DESTDIR = "$$QT.core.libs"
+# TEMPLATE = "lib"
+# _LOADED = "qt_installs" "qt_targets" "qt_build_paths" "qt_common"
+
+## Scopes:
+#####################################################################
+
+#### Keys ignored in scope 3:.:.:winmain.pro:QT_FEATURE_debug_and_release:
+# CONFIG = "build_all"
+
+#### Keys ignored in scope 4:.:.:winmain.pro:MSVC:
+# QMAKE_CFLAGS_DEBUG = "--Zi" "-Z7"
+
+extend_target(qtLibraryTarget$$TARGET$$QT_LIBINFIX CONDITION mingw
+    DEFINES
+        QT_NEEDS_QMAIN
+)
+
+extend_target(qtLibraryTarget$$TARGET$$QT_LIBINFIX CONDITION WINRT
+    SOURCES
+        qtmain_winrt.cpp
+)
+
+extend_target(qtLibraryTarget$$TARGET$$QT_LIBINFIX CONDITION NOT WINRT
+    SOURCES
+        qtmain_win.cpp
+    LIBRARIES
+        shell32
+)
+
+#### Keys ignored in scope 10:.:.:winmain.pro:else:
+# CONFIG = "-qt"

src/winmain/CMakeLists.txt

@@ -0,0 +1,28 @@
+# special case begin
+if (NOT WIN32)
+    return()
+endif()
+
+add_qt_module(WinMain
+  STATIC
+  NO_MODULE_HEADERS
+  DEFINES
+      QT_NO_FOREACH
+  INCLUDE_DIRECTORIES
+      $<TARGET_PROPERTY:Qt::Core,INTERFACE_INCLUDE_DIRECTORIES>
+)
+
+extend_target(WinMain CONDITION WINRT
+    SOURCES qtmain_winrt.cpp
+)
+
+extend_target(WinMain CONDITION NOT WINRT
+    SOURCES qtmain_win.cpp
+)
+
+extend_target(WinMain CONDITION MINGW
+    DEFINES QT_NEEDS_QMAIN
+)
+
+extend_target(Core LIBRARIES WinMain)
+# special case end