patch 8.2.1842: crash when USE_FNAME_CASE is defined and using :browse

Problem:    Crash when USE_FNAME_CASE is defined and using :browse.
Solution:   Don't use read-only memory for ".". (Yegappan Lakshmanan,
            closes #7123)

src/ex_cmds.c

@@ -2465,6 +2465,7 @@ do_ecmd(
     bufref_T	old_curbuf;
     char_u	*free_fname = NULL;
 #ifdef FEAT_BROWSE
+    char_u	dot_path[] = ".";
     char_u	*browse_file = NULL;
 #endif
     int		retval = FAIL;
@@ -2511,7 +2512,7 @@ do_ecmd(
 		// No browsing supported but we do have the file explorer:
 		// Edit the directory.
 		if (ffname == NULL || !mch_isdir(ffname))
-		    ffname = (char_u *)".";
+		    ffname = dot_path;
 	    }
 	    else
 	    {

src/ex_docmd.c

@@ -6084,6 +6084,7 @@ ex_splitview(exarg_T *eap)
     char_u	*fname = NULL;
 #endif
 #ifdef FEAT_BROWSE
+    char_u	dot_path[] = ".";
     int		browse_flag = cmdmod.browse;
 #endif
     int		use_tab = eap->cmdidx == CMD_tabedit
@@ -6136,7 +6137,7 @@ ex_splitview(exarg_T *eap)
 	    // No browsing supported but we do have the file explorer:
 	    // Edit the directory.
 	    if (*eap->arg == NUL || !mch_isdir(eap->arg))
-		eap->arg = (char_u *)".";
+		eap->arg = dot_path;
 	}
 	else
 	{

src/testdir/test_edit.vim

@@ -1805,4 +1805,22 @@ func Test_edit_lastline_scroll()
   close!
 endfunc
 
+func Test_edit_browse()
+  " in the GUI this opens a file picker, we only test the terminal behavior
+  CheckNotGui
+
+  " ":browse xxx" checks for the FileExplorer augroup and assumes editing "."
+  " works then.
+  augroup FileExplorer
+    au!
+  augroup END
+
+  " When the USE_FNAME_CASE is defined this used to cause a crash.
+  browse enew
+  bwipe!
+
+  browse split
+  bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1842,
 /**/
     1841,
 /**/