[Libreoffice] ccache support

[Terrence Enger]

Talking about compression of the ccache cache, ...
On Fri, 2011-09-09 at 11:35 -0500, Norbert Thiebaud wrote:
> 
> Well, my boxes are usually cpu bound (even with a fully hot ccache)
> and I have plenty of space for my ccache, so that is not that clear a
> choice to me.

So, unconditional compression is no good.

> you can set that up with an env variable right ? so you can easily
> make ccache behave the way you want, 'automatically', for you. (i.e
> export CCACHE_COMPRESS=1 in your bashrc)

Yes, it is the existence of the envvar that controls.

Setting it in .bashrc makes a lot of sense in that the relative
availability of I/O capacity vs. CPU capacity does not depend on what
product the user is building.  The use of .bashrc is so easy and
natural (thank you for reminding me about it!) that I think LO should
not even provide a configuration option for compression.

I notice, BTW, that "How to build LibreOffice"
<http://wiki.documentfoundation.org/Development/How_to_build> no
longer says that we automatically enable ccache if it is found on the
system.  Should that statement be added back to the page, now that it
is true?

> 
> I don't do that in configure for the same reason we don't change
> CCACHE_DIR or the cache dir size.
> Using ccache if available is one thing... but trying to
> 'auto-magically' optimize ccache is another can of worms altogether...

Agree.  Especially so, considering that sometimes a cache may be
shared between different users and different systems.