CMake: add support for NO_CONFIG

- A C++ module should set NO_CONFIG to flag that it doesn't have a
   config file (this is an error if it secretly **does** have one)

CMakeModules/CalamaresAddPlugin.cmake

@@ -38,6 +38,7 @@
 #   [RESOURCES resource-file]
 #   [REQUIRES module-name...]
 #   [NO_INSTALL]
+#   [NO_CONFIG]
 #   [SHARED_LIB]
 #   [EMERGENCY]
 # )
@@ -71,7 +72,7 @@ include( CMakeColors )
 function( calamares_add_plugin )
     # parse arguments ( name needs to be saved before passing ARGN into the macro )
     set( NAME ${ARGV0} )
-    set( options NO_INSTALL SHARED_LIB EMERGENCY )
+    set( options NO_CONFIG NO_INSTALL SHARED_LIB EMERGENCY )
     set( oneValueArgs NAME TYPE EXPORT_MACRO RESOURCES )
     set( multiValueArgs SOURCES UI LINK_LIBRARIES LINK_PRIVATE_LIBRARIES COMPILE_DEFINITIONS REQUIRES )
     cmake_parse_arguments( PLUGIN "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN} )
@@ -90,6 +91,9 @@ function( calamares_add_plugin )
     message( "   ${Green}LINK_PRIVATE_LIBRARIES:${ColorReset} ${PLUGIN_LINK_PRIVATE_LIBRARIES}" )
     message( "   ${Green}PLUGIN_DESTINATION:${ColorReset} ${PLUGIN_DESTINATION}" )
     if( PLUGIN_CONFIG_FILES )
+        if( PLUGIN_NO_CONFIG )
+            message( FATAL_ERROR "${Red}NO_CONFIG${ColorReset} is set, with configuration ${Red}${PLUGIN_CONFIG_FILES}${ColorReset}" )
+        endif()
         set( _destination "(unknown)" )
         if ( INSTALL_CONFIG AND NOT PLUGIN_NO_INSTALL )
             set( _destination "${PLUGIN_DATA_DESTINATION}" )
@@ -100,6 +104,10 @@ function( calamares_add_plugin )
             set( _destination "[Skipping installation]" )
         endif()
         message( "   ${Green}CONFIGURATION_FILES:${ColorReset} ${PLUGIN_CONFIG_FILES} => ${_destination}" )
+    else()
+        if( NOT PLUGIN_NO_CONFIG )
+            message( "   ${Red}NO_CONFIG${ColorReset} should be set." )
+        endif()
     endif()
     if( PLUGIN_RESOURCES )
         message( "   ${Green}RESOURCES:${ColorReset} ${PLUGIN_RESOURCES}" )
@@ -170,6 +178,9 @@ function( calamares_add_plugin )
         if ( PLUGIN_EMERGENCY )
             file( APPEND ${_file} "emergency: true\n" )
         endif()
+        if ( NO_CONFIG )
+            file( APPEND ${_file} "noconfig: true\n" )
+        endif()
     endif()
 
     if ( NOT PLUGIN_NO_INSTALL )

src/modules/summary/CMakeLists.txt

@@ -9,4 +9,5 @@ calamares_add_plugin( summary
     LINK_PRIVATE_LIBRARIES
         calamaresui
     SHARED_LIB
+    NO_CONFIG
 )