text: remove a redundant undo element

Implement its single use case by making better use of another element.

src/nano.h

@@ -357,13 +357,12 @@ typedef struct undo {
 	/* Copy of the cutbuffer. */
     filestruct *cutbottom;
 	/* Copy of cutbottom. */
-    bool mark_set;
-	/* Was the marker set when we cut? */
     ssize_t mark_begin_lineno;
-	/* copy copy copy */
+	/* Mostly the line number of the current line; sometimes something else. */
     size_t mark_begin_x;
-	/* Another shadow variable. */
+	/* The x position corresponding to the above line number. */
     struct undo *next;
+	/* A pointer to the undo item of the preceding action. */
 } undo;
 #endif /* !NANO_TINY */
 
@@ -574,8 +573,10 @@ enum
 
 /* Some extra flags for the undo function. */
 #define WAS_FINAL_BACKSPACE	(1<<1)
-#define WAS_MARKED_FORWARD	(1<<2)
-#define WAS_WHOLE_LINE		(1<<3)
+#define WAS_WHOLE_LINE		(1<<2)
+/* The flags for the mark need to be the highest. */
+#define MARK_WAS_SET		(1<<3)
+#define WAS_MARKED_FORWARD	(1<<4)
 #endif /* !NANO_TINY */
 
 /* The maximum number of entries displayed in the main shortcut list. */

src/text.c

@@ -1156,7 +1156,7 @@ void add_undo(undo_type action)
      * no cursor movement in between -- don't add a new undo item. */
     if (u && u->mark_begin_lineno == openfile->current->lineno && action == openfile->last_action &&
 	((action == ADD && u->type == ADD && u->mark_begin_x == openfile->current_x) ||
-	(action == CUT && u->type == CUT && !u->mark_set && keeping_cutbuffer())))
+	(action == CUT && u->type == CUT && u->xflags < MARK_WAS_SET && keeping_cutbuffer())))
 	return;
 
     /* Blow away newer undo items if we add somewhere in the middle. */
@@ -1190,7 +1190,6 @@ void add_undo(undo_type action)
     u->begin = openfile->current_x;
     u->mark_begin_lineno = openfile->current->lineno;
     u->mark_begin_x = openfile->current_x;
-    u->mark_set = FALSE;
     u->wassize = openfile->totsize;
     u->xflags = 0;
     u->grouping = NULL;
@@ -1244,10 +1243,10 @@ void add_undo(undo_type action)
 	break;
     case CUT:
 	cutbuffer_reset();
-	u->mark_set = openfile->mark_set;
-	if (u->mark_set) {
+	if (openfile->mark_set) {
 	    u->mark_begin_lineno = openfile->mark_begin->lineno;
 	    u->mark_begin_x = openfile->mark_begin_x;
+	    u->xflags = MARK_WAS_SET;
 	} else if (!ISSET(CUT_TO_END)) {
 	    /* The entire line is being cut regardless of the cursor position. */
 	    u->begin = 0;
@@ -1379,7 +1378,7 @@ fprintf(stderr, "  >> Updating... action = %d, openfile->last_action = %d, openf
 	    break;
 	free_filestruct(u->cutbuffer);
 	u->cutbuffer = copy_filestruct(cutbuffer);
-	if (u->mark_set) {
+	if (u->xflags == MARK_WAS_SET) {
 	    /* If the "marking" operation was from right-->left or
 	     * bottom-->top, then swap the mark points. */
 	    if ((u->lineno == u->mark_begin_lineno && u->begin < u->mark_begin_x)