Macros for translatable strings that need disambiguating context

locale/update_po_files.sh

@@ -5,7 +5,7 @@ sed -E 's/\.\.\///g' |\
 xargs xgettext \
 --default-domain=audacity \
 --directory=.. \
---keyword=_ --keyword=XO --keyword=XXO --keyword=XP:1,2 \
+--keyword=_ --keyword=XO --keyword=XC:1,2c --keyword=XXO --keyword=XP:1,2 --keyword=XPC:1,2,4c \
 --add-comments=" i18n" \
 --add-location=file  \
 --copyright-holder='Audacity Team' \

src/Internat.h

@@ -32,7 +32,13 @@ extern AUDACITY_DLL_API const wxString& GetCustomSubstitution(const wxString& st
 // '&', preceding menu accelerators, should NOT occur in the argument.
 #define XO(s)  (TranslatableString{ wxT(s), {} })
 
-// Marks strings for extraction only, where '&', preceding men accelerators, MAY
+// Alternative taking a second context argument.  A context is a string literal,
+// which is not translated, but serves to disambiguate uses of the first string
+// that might need differing translations, such as "Light" meaning not-heavy in
+// one place but not-dark elsewhere.
+#define XC(s, c)  (TranslatableString{ wxT(s), {} }.Context(c))
+
+// Marks strings for extraction only, where '&', preceding menu accelerators, MAY
 // occur.
 // For now, expands exactly as macro XO does, but in future there will be a
 // type distinction - for example XXO should be used for menu item names that
@@ -86,6 +92,10 @@ extern AUDACITY_DLL_API const wxString& GetCustomSubstitution(const wxString& st
 #define XP(sing, plur, n) \
    TranslatableString{ wxT(sing), {} }.Plural<(n)>( wxT(plur) )
 
+// Like XP but with an additional context argument, as for XC
+#define XPC(sing, plur, n, c) \
+   TranslatableString{ wxT(sing), {} }.Context(c).Plural<(n)>( wxT(plur) )
+
 #endif
 
 class Internat