Added autoconf support for using OSMesa as the driver instead linking
it to libGL. This is enabled through --with-driver=osmesa.
To differentiate these cases, another option --enable-x11-osmesa is used
to enable or disable building OSMesa when the driver is x11.
Added autoconf bits to allow using DRI as the driver through the option
--with-dri-driver=DRIVER. The options are x11 (default) and dri. Three
DRI specific options for controlling the driver directory, direct
rendering and TLS are also added.
The DRI will probably not work for platforms besides linux and freebsd.
This adds the initial support for using autoconf configuration. Support
is available for shared Xlib driver builds. Later this will be extended
to dri and osmesa-only builds and possibly targetting non-X backends.
Support for static library builds will also be added.
The configure script fills in the autoconf config. This is then used by
running `make autoconf' after ./configure.
Testing has been done on Linux/GNU. The configure script tries to
faithfully reproduce the current configs/linux* and configs/freebsd*.
Other platforms can be handled later by adding similar statements and
feature tests.
Pkg-config is used to search for packages when possible. This makes the
build much more flexible and robust to the user's configuration. This
requires that the pkg-config autoconf macros pkg.m4 are included in
aclocal.m4. This requires autoconf and aclocal from autoconf and
automake, respectively.
Dan Nicholson