[Bug: 21.5-b27] Can't move cursor in edit-faces buffer

[Stephen J. Turnbull]

Ron Isaacson writes:

 > You might argue that #1 is our problem, and that if you specify
 > --with-cppflags, that's an override to the default behavior of
 > inheriting CPPFLAGS. We've got an easy workaround for that, but it
 > still might be something to consider.

It's not properly documented, so that's our problem.

Does `configure --with-cppflags="-newflag $CPPFLAGS" ...' work in your
application?  I think that having the `--with-WHATEVERflags' options
override the corresponding environment variables is easier to
explain.  It's certainly easier to code!

    This option overrides the environment.  If you wish to include the
    flags that may have been specified in CPPFLAGS, this must be done
    explicitly: `--with-cppflags="-addlflag $CPPFLAGS"'.

 > #2 is definitely not our problem. :-) I think you need to ensure that
 > png_err_stct.setjmp_buffer is set to a valid address BEFORE passing
 > png_error_func as a parameter to anything. Otherwise, any runtime
 > error from png_create_read_struct will get you into the same boat.

Thanks for diagnosing this!  I'll have to tweak Jerry about this, this
kind of thing should be catchable via one of those famous static
checkers.:-)

Steve