patch 8.0.0448: some macros are in lower case

Problem:    Some macros are in lower case, which can be confusing.
Solution:   Make a few lower case macros upper case.
diff --git a/src/ex_getln.c b/src/ex_getln.c
index 9180319..d3fda24 100644
--- a/src/ex_getln.c
+++ b/src/ex_getln.c
@@ -234,7 +234,7 @@
 
     ccline.overstrike = FALSE;		    /* always start in insert mode */
 #ifdef FEAT_SEARCH_EXTRA
-    clearpos(&match_end);
+    CLEAR_POS(&match_end);
     save_cursor = curwin->w_cursor;	    /* may be restored later */
     search_start = curwin->w_cursor;
     old_curswant = curwin->w_curswant;
@@ -1479,7 +1479,7 @@
 		    if (did_incsearch)
 		    {
 			curwin->w_cursor = match_end;
-			if (!equalpos(curwin->w_cursor, search_start))
+			if (!EQUAL_POS(curwin->w_cursor, search_start))
 			{
 			    c = gchar_cursor();
 			    /* If 'ignorecase' and 'smartcase' are set and the
@@ -1707,7 +1707,7 @@
 			    search_start = t;
 			    (void)decl(&search_start);
 			}
-			if (lt(t, search_start) && c == Ctrl_G)
+			if (LT_POS(t, search_start) && c == Ctrl_G)
 			{
 			    /* wrap around */
 			    search_start = t;
@@ -2007,7 +2007,7 @@
 	    curwin->w_cursor = save_cursor;
 	else
 	{
-	    if (!equalpos(save_cursor, search_start))
+	    if (!EQUAL_POS(save_cursor, search_start))
 	    {
 		/* put the '" mark at the original position */
 		curwin->w_cursor = save_cursor;