Fix SELUNSET macro. correct at last?

Offer selsrc2dest(), seldest2src().

src/specks.h

@@ -128,7 +128,12 @@ typedef struct _selfunc {
 #define	SELECTED(attrs, selp)	(0==( ((attrs)^(selp)->wanton) & (selp)->wanted))
 #define	SELBYDEST(attrs, selp)  (0==( ((attrs)^(selp)->wanton) & ~(selp)->wanted))
 #define	SELSET(attrs, selp)	((attrs) = ((attrs)&(selp)->wanted) ^ (selp)->wanton)
-#define SELUNSET(attrs, selp)	(((attrs) = ((attrs)&~(selp)->wanton)) | ~(selp)->wanted)
+#define SELUNSET(attrs, selp)	((attrs) = ((attrs)|~(selp)->wanted) ^ (selp)->wanton)
+	/* SET:   want=1 => attrs' = attrs ^ wanton
+	 * 	  want=0 => attrs' = wanton
+	 * UNSET: want=1 => attrs' = attrs ^ wanton
+	 * 	  want=0 => attrs' = ~wanton
+	 */
 
 #define SELMASK(bitno)		(((SelMask)1) << ((bitno)-1))
 
@@ -427,6 +432,7 @@ extern int   specks_check_async( struct stuff ** );
 extern void  specks_set_annotation( struct stuff *, CONST char *str );
 
 extern void  specks_current_frame( struct stuff *, struct specklist *sl );
+extern void  specks_reupdate( struct stuff *, struct specklist *sl );
 extern void  specks_datawait( struct stuff * );
 
 extern struct specklist * specks_timespecks( struct stuff *, int dataset, int timestep );
@@ -441,6 +447,8 @@ extern int getbool( char *str, int what );
 extern int parse_selexpr( struct stuff *, char *str, SelOp *dest, SelOp *src, char *plaint );
 extern char *show_selexpr( struct stuff *, SelOp *dest, SelOp *src );
 extern void selinit( SelOp * );
+extern void selsrc2dest( struct stuff *, CONST SelOp *src, SelOp *dest );
+extern void seldest2src( struct stuff *, CONST SelOp *dest, SelOp *src );
 
 extern SpecksPickFunc specks_all_picks( struct stuff *, SpecksPickFunc func, void *arg );