Document GH_SUBDIR.

[mat]

• Add an example on how to do work with git submodules.

[wblock]

en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml

1996–1997

Remove "all"

1998

s/one/a single/

2183

"What it basically does" is not needed. Better to just name it and use the present tense. Also, the subdirectory name should be in <filename> tags when being referred to as a directory (rather than a value to be set).

<varname>GH_SUBDIR</varname> makes sure that
<filename>ext</filename> exists, but that
<filename>ext/icons</filename> does not already exist.  Then it
does this:</para>

2221

Seems like this could be simpler:

Ports with GitHub as an upstream repository sometimes use submodules.

2223

Can probably end the sentence after "information".

2227

s/need to be/must be/

2232

Extra space between "example," and "its".

2236

file at the root.  This file describes all the submodules used in this repository, and lists additional repositories needed.

2285

Break sentence here. s/, each/. Each/

2286

"in fact" is not needed.

2294

<command>git submodule status</command> will provide more

2295

Break sentence here:

meaningful information.  For example, here,

2300

Why?

2303

s/have/has/ (singular)

2305

(only GitHub-related lines are shown):</para>

[mat]

en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml

2232

Ah, yes, igor does not report it :-p

2300

Because i said so, 4 lines above, it gives more meaning to it. And I did not want to repeat myself :-)
It's more interesting to use v3.4.0 as it show it is using a "release" and not a specific hash that upstream picked out of a hat.

Also, it has the advantage that if there is a wxsqlite3 port using github and using version 3.4.0, its distfile will be the same, and you get one distfile for two ports and save some space.

[mat]

• With wblock's comments.

[mat]

• Add it to option helpers.

[wblock]

en_US.ISO8859-1/books/porters-handbook/makefiles/chapter.xml

2300

Above, it just says "will provide more meaningful information". It doesn't tell how the information given is more meaningful. If it isn't possible to be more specific, probably better to make this imperative rather than a suggestion:

Both can be used
interchangeably, but when a tag is available, use it.</para>

[mat]

This was committed in rD49366.