bug#20663: page.el (forward-page): Avoid skipping pages

[Pierre Neidhardt]

When `page-delimiter` starts at the beginning of the line and the position is
also at the beginning of the line, calling `forward-page` will skip one page.

Running `emacs -Q example.txt`:

        M-<
        C-x n p
        M->
        M-1 C-x n p

This should bring us from page 1 to page 2, but page 3 gets displayed instead.

The attached patch fixes it by changing the code to actually match its
surrounding comments.


In GNU Emacs 24.5.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.16.2)
 of 2015-04-20 on bitzer.hoetzel.info
Windowing system distributor `The X.Org Foundation', version 11.0.11701000
System Description:     Arch Linux

Configured using:
 `configure --prefix=/usr --sysconfdir=/etc --libexecdir=/usr/lib
 --localstatedir=/var --with-x-toolkit=gtk3 --with-xft
 'CFLAGS=-march=x86-64 -mtune=generic -O2 -pipe -fstack-protector-strong
 --param=ssp-buffer-size=4' CPPFLAGS=-D_FORTIFY_SOURCE=2
 LDFLAGS=-Wl,-O1,--sort-common,--as-needed,-z,relro'

Important settings:
  value of $LC_MESSAGES: sv_SE.UTF-8
  value of $LANG: sv_SE.UTF-8
  locale-coding-system: utf-8-unix

-- 
Pierre Neidhardt

Virginia law forbids bathtubs in the house; tubs must be kept in the yard.

ChangeLog
Description: Text document

example.txt
Description: Text document

page.patch
Description: Text Data