runtime(ftplugin): Use "*" browsefilter pattern to match "All Files"

Problem:  The "*.*" browsefilter pattern only matches all files on
	  Windows (Daryl Lee)
Solution: Use "*" to filter on all platforms but keep "*.*" as the label
	  text on Windows. (Fixes #12685, Doug Kearns)

The *.* browsefilter pattern used to match "All Files" on Windows is a
legacy of the DOS 8.3 filename wildcard matching algorithm.  For reasons
of backward compatibility this still works on Windows to match all
files, even those without an extension.

However, this pattern only matches filenames containing a dot on other
platforms.  This often makes files without an extension difficult to
access from the file dialog, e.g., "Makefile"

On Windows it is still standard practice to use "*.*" for the filter
label so ftplugins should use "All Files (*.*)" on Windows and "All
Files (*)" on other platforms.  This matches Vim's default browsefilter
values.

This commit also normalises the browsefilter conditional test to check
for the Win32 and GTK GUI features and an unset b:browsefilter.

closes: #12759

Signed-off-by: Doug Kearns <dougkearns@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/ftplugin/vhdl.vim b/runtime/ftplugin/vhdl.vim
index ff56166..3850c70 100644
--- a/runtime/ftplugin/vhdl.vim
+++ b/runtime/ftplugin/vhdl.vim
@@ -3,6 +3,7 @@
 " Maintainer:  R.Shankar <shankar.pec?gmail.com>
 " Modified By: Gerald Lai <laigera+vim?gmail.com>
 " Last Change: 2011 Dec 11
+"              2024 Jan 14 by Vim Project (browsefilter)
 "              2023 Aug 28 by Vim Project (undo_ftplugin, commentstring)
 
 " Only do this when not done yet for this buffer
@@ -28,14 +29,15 @@
 " Format comments to be up to 78 characters long
 "setlocal tw=75
 
-" let b:undo_ftplugin = "setl cms< com< fo< tw<"
-
 let b:undo_ftplugin = "setl cms< "
 
-" Win32 can filter files in the browse dialog
-"if has("gui_win32") && !exists("b:browsefilter")
-"  let b:browsefilter = "Verilog Source Files (*.v)\t*.v\n" .
-"   \ "All Files (*.*)\t*.*\n"
+" Win32 and GTK can filter files in the browse dialog
+"if (has("gui_win32") || has("gui_gtk")) && !exists("b:browsefilter")
+"  if has("win32")
+"    let b:browsefilter ..= "All Files (*.*)\t*\n"
+"  else
+"    let b:browsefilter ..= "All Files (*)\t*\n"
+"  endif
 "  let b:undo_ftplugin .= " | unlet! b:browsefilter"
 "endif