c++: fix position operator signatures

* data/location.cc (operator+=, operator-=): Remove const from return
type.

diff --git a/data/location.cc b/data/location.cc
index 92b6d0967fad7dfbaa8e1ebb3630b6c28ca00526..49f5f349534d67d3d64c178e4e94728b7a50d5df 100644 (file)
--- a/data/location.cc
+++ b/data/location.cc
@@ -87,7 +87,7 @@ b4_copyright([Positions for Bison parsers in C++],
   };
 
   /// Add and assign a position.
-  inline const position&
+  inline position&
   operator+= (position& res, const int width)
   {
     res.columns (width);
@@ -103,7 +103,7 @@ b4_copyright([Positions for Bison parsers in C++],
   }
 
   /// Add and assign a position.
-  inline const position&
+  inline position&
   operator-= (position& res, const int width)
   {
     return res += -width;