tweaks: elide a parameter and a return value

As 'filepart' is a global variable, there is no need to pass it around.
Just use it directly.

src/files.c

@@ -2000,7 +2000,7 @@ bool write_marked_file(const char *name, FILE *f_open, bool tmp,
 	/* Partition the buffer so that it contains only the marked text. */
 	get_region((const linestruct **)&top, &top_x,
 				(const linestruct **)&bot, &bot_x, NULL);
-	filepart = partition_buffer(top, top_x, bot, bot_x);
+	partition_buffer(top, top_x, bot, bot_x);
 
 	/* If we are using a magic line, and the last line of the partition
 	 * isn't blank, then add a newline at the end of the buffer. */
@@ -2015,7 +2015,7 @@ bool write_marked_file(const char *name, FILE *f_open, bool tmp,
 		remove_magicline();
 
 	/* Unpartition the buffer so that it contains all the text again. */
-	unpartition_buffer(&filepart);
+	unpartition_buffer();
 
 	return retval;
 }

src/nano.c

@@ -192,8 +192,8 @@ void renumber_from(linestruct *line)
 
 /* Partition the current buffer so that it appears to begin at (top, top_x)
  * and appears to end at (bot, bot_x). */
-partition *partition_buffer(linestruct *top, size_t top_x,
-		linestruct *bot, size_t bot_x)
+void partition_buffer(linestruct *top, size_t top_x,
+						linestruct *bot, size_t bot_x)
 {
 	partition *p = nmalloc(sizeof(partition));
 
@@ -230,14 +230,15 @@ partition *partition_buffer(linestruct *top, size_t top_x,
 	/* Remove all text before top_x at the top of the partition. */
 	charmove(top->data, top->data + top_x, strlen(top->data) - top_x + 1);
 
-	/* Return the partition. */
-	return p;
+	filepart = p;
 }
 
 /* Unpartition the current buffer so that it stretches from (filetop, 0)
  * to (filebot, $) again. */
-void unpartition_buffer(partition **p)
+void unpartition_buffer()
 {
+	partition **p = &filepart;
+
 	/* Reattach the line above the top of the partition, and restore the
 	 * text before top_x from top_data.  Free top_data when we're done
 	 * with it. */
@@ -270,8 +271,8 @@ void unpartition_buffer(partition **p)
 		openfile->filebot = (*p)->filebot;
 
 	/* Uninitialize the partition. */
-	free(*p);
-	*p = NULL;
+	free(filepart);
+	filepart = NULL;
 }
 
 /* Move all text between (top, top_x) and (bot, bot_x) from the current buffer
@@ -293,7 +294,7 @@ void extract(linestruct *top, size_t top_x, linestruct *bot, size_t bot_x)
 	 * (top, top_x) to (bot, bot_x), keep track of whether the top of
 	 * the edit window is inside the partition, and keep track of
 	 * whether the mark begins inside the partition. */
-	filepart = partition_buffer(top, top_x, bot, bot_x);
+	partition_buffer(top, top_x, bot, bot_x);
 	edittop_inside = (openfile->edittop->lineno >= openfile->filetop->lineno &&
 						openfile->edittop->lineno <= openfile->filebot->lineno);
 #ifndef NANO_TINY
@@ -358,7 +359,7 @@ void extract(linestruct *top, size_t top_x, linestruct *bot, size_t bot_x)
 
 	/* Unpartition the buffer so that it contains all the text
 	 * again, minus the saved text. */
-	unpartition_buffer(&filepart);
+	unpartition_buffer();
 
 	renumber_from(openfile->current);
 
@@ -394,8 +395,8 @@ void ingraft_buffer(linestruct *topline)
 
 	/* Partition the buffer so that it contains no text, and remember
 	 * whether the current line is at the top of the edit window. */
-	filepart = partition_buffer(openfile->current, openfile->current_x,
-								openfile->current, openfile->current_x);
+	partition_buffer(openfile->current, openfile->current_x,
+						openfile->current, openfile->current_x);
 	edittop_inside = (openfile->edittop == openfile->filetop);
 	delete_node(openfile->filetop);
 
@@ -437,7 +438,7 @@ void ingraft_buffer(linestruct *topline)
 
 	/* Unpartition the buffer so that it contains all the text
 	 * again, plus the copied text. */
-	unpartition_buffer(&filepart);
+	unpartition_buffer();
 
 	renumber_from(topline);
 
@@ -576,7 +577,7 @@ void die(const char *msg, ...)
 		 * because it would write files not mentioned on the command line. */
 		if (openfile->modified && !ISSET(RESTRICTED)) {
 			if (filepart != NULL)
-				unpartition_buffer(&filepart);
+				unpartition_buffer();
 
 			emergency_save(openfile->filename, openfile->current_stat);
 		}

src/proto.h

@@ -393,9 +393,9 @@ void delete_node(linestruct *fileptr);
 linestruct *copy_buffer(const linestruct *src);
 void free_lines(linestruct *src);
 void renumber_from(linestruct *line);
-partition *partition_buffer(linestruct *top, size_t top_x,
+void partition_buffer(linestruct *top, size_t top_x,
 		linestruct *bot, size_t bot_x);
-void unpartition_buffer(partition **p);
+void unpartition_buffer();
 void extract(linestruct *top, size_t top_x, linestruct *bot, size_t bot_x);
 void ingraft_buffer(linestruct *somebuffer);
 void copy_from_buffer(linestruct *somebuffer);

src/text.c

@@ -3039,7 +3039,7 @@ void do_wordlinechar_count(void)
 	if (openfile->mark) {
 		get_region((const linestruct **)&top, &top_x,
 					(const linestruct **)&bot, &bot_x, NULL);
-		filepart = partition_buffer(top, top_x, bot, bot_x);
+		partition_buffer(top, top_x, bot, bot_x);
 	}
 
 	/* Start at the top of the file. */
@@ -3063,7 +3063,7 @@ void do_wordlinechar_count(void)
 	/* Get the number of multibyte characters, similar to "wc -c". */
 	if (openfile->mark) {
 		chars = get_totsize(openfile->filetop, openfile->filebot);
-		unpartition_buffer(&filepart);
+		unpartition_buffer();
 	} else
 		chars = openfile->totsize;