libstdc++ in gcc3.
when defined, USE_GCC_SHLIB ensures that the correct rpath is passed
to the linker, and a full dependency on the compiler package is
registered.
packages which define USE_GCC_SHLIB should not include
mk/gcc.buildlink2.mk (or gcc{,3}/buildlink2.mk) as it is handled
automatically.
has not yet been strongly buildlinked. However, we need to indicate that
the package needs X11 to build, so fall back to USE_X11=yes.
Fixes a problem in the i386 bulk build.
* It's CONFIGURE_ARGS, not CONFIGURE_ARG.
* Use Mesa/buildlink.mk to properly handle whether we're using XF3 or XF4
(the latter contains its own MesaGL libraries).
* Comment out inclusion of x11.buildlink.mk since we're not even weakly
buildlinked, so jumping ahead to trying to strongly buldlinkify this
package is overboard.
* Sort the buildlink.mk file (just personal aesthetics).
environment variable and the $HOME/.xplanet directory) for users to
maintain data sets and images for xplanet without having to them in
${LOCALBASE}/share/xplanet.
