Customize buttons that change user's custom file should ask for confirmation

[Drew Adams]

The Customize buttons now work with either mouse-1 or mouse-2, but
mouse-1 is used all the time in Emacs to point and move the text
cursor. Some of the global Customize buttons have very important
effects, and they should not be acted on without confirmation from the
user.

For example, if you accidentally or mistakenly click mouse-1 (or mouse
2) on the text (button) Reset to Standard (Erase Customization), all
of your customizations in your custom file are wiped out! (all of the
preferences that were visible in the Customize buffer, that is - which
might be all of them). You are reduced to a standard-issue Emacs,
after perhaps multiple customizations over a long period of
time. Unless you have a backup of your custom-file, you are really
SOL.

This is an important UI bug, with potentially disastrous
consequences. Any button, menu item, or command that changes a user
file - especially .emacs or custom-file, should ask for confirmation
first.

What's more, this particular action gives no feedback that your custom
file has been modified, and its name is misleading. It is the only
Reset button that changes your custom file. Erase Customization is a
bad name - it can imply just the opposite from a permanent change; it
can give the impression that your buffer changes will just be erased
(reset of edit fields). The name should be Reset to Standard, as it
was in Emacs 20, and, most importantly, it should ask for confirmation
before doing anything.


In GNU Emacs 21.3.50.1 (i386-mingw-nt5.1.2600)
 of 2004-07-26 on BERATUNG4
configured using `configure --with-gcc
(3.3) --cflags -I../../jpeg-6b-1/include -I../../libpng-1.2.4-1/include -I..
/../tiff-3.5.7/include -I../../xpm-nox-4.2.0/include -I../../zlib-1.1.4-1/in
clude'