Add missing -help argument to qt-configure-module

Now it's possible to display a configure help screen per module with
  qt-configure-module <module-source-dir> -help

Pick-to: 6.2
Fixes: QTBUG-95943
Change-Id: I7d26006246af4b38b5a2ec6deca3f45c5313afec
Reviewed-by: Alexey Edelev <alexey.edelev@qt.io>
Reviewed-by: Alexandru Croitor <alexandru.croitor@qt.io>

bin/qt-configure-module.bat.in

@@ -28,4 +28,7 @@ goto :eof
 
 :print_usage
 echo Usage: qt-configure-module ^<module-source-dir^> [options]
+echo.
+echo To display the available options for a Qt module, run
+echo qt-configure-module ^<module-source-dir^> -help
 goto :eof

bin/qt-configure-module.in

@@ -4,7 +4,12 @@ script_dir_path=`(cd "$script_dir_path"; /bin/pwd)`
 
 printUsage()
 {
-    echo 'Usage: qt-configure-module <module-source-dir> [options]'
+    cat <<EOF
+Usage: qt-configure-module <module-source-dir> [options]
+
+To display the available options for a Qt module, run
+qt-configure-module <module-source-dir> -help
+EOF
 }
 
 if [ "$#" -lt 1 ]; then

cmake/QtProcessConfigureArgs.cmake

@@ -71,6 +71,8 @@ while(NOT "${configure_args}" STREQUAL "")
         set(auto_detect_compiler FALSE)
     elseif(arg STREQUAL "-list-features")
         set(list_features TRUE)
+    elseif(arg MATCHES "^-h(elp)?$")
+        set(display_module_help TRUE)
     elseif(arg STREQUAL "-write-options-for-conan")
         list(POP_FRONT configure_args options_json_file)
     elseif(arg STREQUAL "-skip")
@@ -439,6 +441,26 @@ function(qt_call_function func)
     endif()
 endfunction()
 
+if(display_module_help)
+    message([[
+Options:
+  -help, -h ............ Display this help screen
+
+  -feature-<feature> ... Enable <feature>
+  -no-feature-<feature>  Disable <feature> [none]
+  -list-features ....... List available features. Note that some features
+                         have dedicated command line options as well.
+]])
+
+    set(help_file "${MODULE_ROOT}/config_help.txt")
+    if(EXISTS "${help_file}")
+        file(READ "${help_file}" content)
+        message("${content}")
+    endif()
+
+    return()
+endif()
+
 if(list_features)
     unset(lines)
     foreach(feature ${commandline_known_features})