-enable-build-help is now the default behaviour

[Sylvestre Ledru]

Hello,

I just made a small change in the configure.
Now, a default ./configure will look for the documentation dependencies
and enables the doc target in the Makefile.
If you wan to disable the checks and the build, use the option
--disable-build-help in the configure.

There is no more reason to disable it by default (it used to be like
that when we were working on this part).

Sylvestre