Re: obsolete comment in tool-bar.el

[Richard M. Stallman]

This is good, but

    + These two functions are only meant for options defined in pre-loaded
    + files, where some variables or functions used to compute the option's
    + value may not yet be defined.  The option normally gets updated in
    + @file{startup.el}, ignoring the previously computed value.  Because of
    + this typical usage, the value which these two functions compute
    + normally only matters when, after startup, one unsets the option's
    + value and then reevaluates the defcustom.

To make that really clear, I think you should add:

  By that time, the necessary variables and functions will be defined,
  so there will not be an error.