Log message:
Fix build with GCC 4.5

Log message:
Convert @exec/@unexec to @pkgdir or drop them.

Log message:
Remove @dirrm entries from PLISTs

Log message:
Simply and speed up buildlink3.mk files and processing.
This changes the buildlink3.mk files to use an include guard for the
recursive include. The use of BUILDLINK_DEPTH, BUILDLINK_DEPENDS,
BUILDLINK_PACKAGES and BUILDLINK_ORDER is handled by a single new
variable BUILDLINK_TREE. Each buildlink3.mk file adds a pair of
enter/exit marker, which can be used to reconstruct the tree and
to determine first level includes. Avoiding := for large variables
(BUILDLINK_ORDER) speeds up parse time as += has linear complexity.
The include guard reduces system time by avoiding reading files over and
over again. For complex packages this reduces both %user and %sys time to
half of the former time.

Log message:
The package supports installation to DESTDIR.

Log message:
malloc.h --> stdlib.h

Log message:
make this build with newer g++

Log message:
Needs OVERRIDE_DIRDEPTH=3.

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:
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