[gtkada] improvements to the GtkAda build system

[Arnaud Charlet]

> · In Fedora we package only shared libraries in most cases. Static libraries
> are packaged only when they are needed for some specific reason. Therefore I
> added the configuration options --enable-static and --disable-static,
> which
> control the variable BUILD_STATIC in the makefiles. The default is to build
> static libraries, like before.

Apparently you've changed DEFAULT_LIBRARY_TYPE to be shared by default, which
is not what we want.

Note that you'r patch contains lots of different changes, some which may not be
desirable, some which may.

I would suggest splitting the change into small patches, that will make
it much easier to review the changes, and to integrate them.

In particular, the DESTDIR change is mostly mechanical and orthogonal to the
other changes, so I'd suggest creating a standalone patch for this
change.

Same for debuginfo, for --enable-static, etc...

Arno