Log message:
Fix !defined(IS_BUILTIN.xproto) inherited when this was copied from
xproto; should have been .renderproto so that the variable always gets
defined somehow.  (Under older bmake, there was a syntax error when
IS_BUILTIN.renderproto was later checked, because for x11-links, it was
never defined in the first place.)

Remove check for X11BASE==LOCALBASE.  There's even a comment there saying
we don't want to check that, so don't do it.

Log message:
For reasons beyond my compressions, (b)make handles

.if foo || bar
BAZ=	no
.else
BAZ=	yes
.endif

different from

.if foo
BAZ=	no
.elif bar
BAZ=	no
.else
BAZ=	yes
.endif

in some situations exposed in this builtin.mk. Workaround this for now.

Log message:
Don't assume that we have a builtin version of the X11 proto packages,
if LOCALBASE and X11BASE are identical.

Log message:
Replace mk/bsd.prefs.mk includes with bsd.fast.prefs.mk includes.
The redundant parsing of bsd.prefs.mk is mostly avoided now and
parse time e.g. for x11/kdebase3 gets reduced by up to 10%.

Log message:
Support DESTDIR. Take maintainership.

Log message:
The shell code to symlink the pkg-config file is hidden as usual.

Log message:
Added "c" to USE_LANGUAGES for packages that use GNU configure scripts,
since they always need a C compiler, even when the source code is
completely in C++.

For some other packages, stated in the comment that a C compiler is
really not needed.

Log message:
Don't use the builtin framework for the various Xorg components
when X11_TYPE=xorg. Let them include x11.buildlink3.mk directly.
Remove the manual USE_BUILTIN declarations from xorg-libs/b3.mk.
This fixes a symmetry in the dependency list depending on whether
xorg-libs is installed already or not.

Discussed with jlam@

Log message:
Change the format of BUILDLINK_ORDER to contain depth information as well,
and add a new helper target and script, "show-buildlink3", that outputs
a listing of the buildlink3.mk files included as well as the depth at
which they are included.

For example, "make show-buildlink3" in fonts/Xft2 displays:

	zlib
	fontconfig
	    iconv
	    zlib
	    freetype2
	    expat
	freetype2
	Xrender
	    renderproto

Log message:
Track information in a new variable BUILDLINK_ORDER that informs us
of the order in which buildlink3.mk files are (recursively) included
by a package Makefile.