Recognize C++ conversion operators with trailing '= 0' as abstract

This fix is done for all supported variants of user-defined conversion
operators and fixes swig#1723.

Author: Thomas REITMAYR

Source/CParse/parser.y

@@ -4800,6 +4800,9 @@ cpp_conversion_operator : storage_class CONVERSIONOPERATOR type pointer LPAREN p
 		 if ($8.qualifier) {
 		   SwigType_push($4,$8.qualifier);
 		 }
+		 if ($8.val) {
+		   Setattr($$,"value",$8.val);
+		 }
 		 Setattr($$,"refqualifier",$8.refqualifier);
 		 Setattr($$,"decl",$4);
 		 Setattr($$,"parms",$6);
@@ -4818,6 +4821,9 @@ cpp_conversion_operator : storage_class CONVERSIONOPERATOR type pointer LPAREN p
 		 if ($8.qualifier) {
 		   SwigType_push(decl,$8.qualifier);
 		 }
+		 if ($8.val) {
+		   Setattr($$,"value",$8.val);
+		 }
 		 Setattr($$,"refqualifier",$8.refqualifier);
 		 Setattr($$,"decl",decl);
 		 Setattr($$,"parms",$6);
@@ -4836,6 +4842,9 @@ cpp_conversion_operator : storage_class CONVERSIONOPERATOR type pointer LPAREN p
 		 if ($8.qualifier) {
 		   SwigType_push(decl,$8.qualifier);
 		 }
+		 if ($8.val) {
+		   Setattr($$,"value",$8.val);
+		 }
 		 Setattr($$,"refqualifier",$8.refqualifier);
 		 Setattr($$,"decl",decl);
 		 Setattr($$,"parms",$6);
@@ -4856,6 +4865,9 @@ cpp_conversion_operator : storage_class CONVERSIONOPERATOR type pointer LPAREN p
 		 if ($9.qualifier) {
 		   SwigType_push(decl,$9.qualifier);
 		 }
+		 if ($9.val) {
+		   Setattr($$,"value",$9.val);
+		 }
 		 Setattr($$,"refqualifier",$9.refqualifier);
 		 Setattr($$,"decl",decl);
 		 Setattr($$,"parms",$7);
@@ -4873,7 +4885,10 @@ cpp_conversion_operator : storage_class CONVERSIONOPERATOR type pointer LPAREN p
 		if ($7.qualifier) {
 		  SwigType_push(t,$7.qualifier);
 		}
-		 Setattr($$,"refqualifier",$7.refqualifier);
+		if ($7.val) {
+		  Setattr($$,"value",$7.val);
+		}
+		Setattr($$,"refqualifier",$7.refqualifier);
 		Setattr($$,"decl",t);
 		Setattr($$,"parms",$5);
 		Setattr($$,"conversion_operator","1");