framework preferences: add option for Control+Alt as AltGr

gui-lib/framework/private/main.rkt

@@ -214,6 +214,10 @@
 (preferences:add-callback 'framework:special-meta-key (λ (p v) (map-command-as-meta-key v)))
 (map-command-as-meta-key (preferences:get 'framework:special-meta-key))
 
+(preferences:set-default 'framework:any-control+alt-is-altgr #f boolean?)
+(preferences:add-callback 'framework:any-control+alt-is-altgr (λ (p v) (any-control+alt-is-altgr v)))
+(any-control+alt-is-altgr (preferences:get 'framework:any-control+alt-is-altgr))
+
 (preferences:set-default 'framework:fraction-snip-style 
                          'mixed (λ (x) (memq x '(mixed improper decimal))))
 

gui-lib/framework/private/preferences.rkt

@@ -478,6 +478,11 @@ the state transitions / contracts are:
                                 'framework:special-meta-key
                                 (string-constant command-as-meta)))
                    
+                   (when (memq (system-type) '(windows))
+                     (add-check editor-panel 
+                                'framework:any-control+alt-is-altgr
+                                (string-constant any-control+alt-is-altgr)))
+                   
                    (add-check editor-panel 
                               'framework:coloring-active
                               (string-constant online-coloring-active))

gui-lib/info.rkt

@@ -12,7 +12,7 @@
                "pict-lib"
                "scheme-lib"
                "scribble-lib"
-               ["string-constants-lib" #:version "1.7"]
+               ["string-constants-lib" #:version "1.9"]
                "option-contract-lib"
                "2d-lib"
                "compatibility-lib"