You can use it like 'make install', or 'make install prefix=/path', to override
what has been set by ./configure.

So that the message about what to do now (issue make and make dev-install) is
the last thing the user sees.

futhermore: the conf.log extraction method is no reliable. autoconf
has changed and newer version don't put it there.
furthermore, because of the post_download generation,
the conf.log get crowded by a second autoconf...

on windows, the configure check that some dll/exe are present.
these are in fact automatically downloaded by the ./download script.
but that script is run _after_ ./configure.
So the tests are postponed and run in a post_download script that is
invoked at the end of the download script.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

based on kohei blog on the subject, adapted for the 'bootstrap' build

Use bash substitution, instead of a piped sed

This is the first step in removing the need for the 'build' repository, and
its 'rawbuild' hack.

Let's try our best to create a good list of langauges in a format
of lang1,lang2.
Also remove the wanted function which is not used since
the baab40f5646b63ff51e7cb9c5aaac873066d46fe commit.

 Introduces:
 --enable-extra-gallery  - for additional galleries
 --enable-extra-template - for additional templates
 --enable-extra-sample   - for additional samples
 --enable-extra-font     - for additional fonts
 configure options.