Log message:
Fix indentation in buildlink3.mk files.

The actual fix as been done by "pkglint -F */*/buildlink3.mk", and was
reviewed manually.

There are some .include lines that still are indented with zero spaces
although the surrounding .if is indented. This is existing practice.

Log message:
Add SHA512 digests for distfiles for x11 category

Problems found locating distfiles:
        Package modular-xorg-server: missing distfile xorg-server-1.17.4.tar.bz2
        Package py-qt4: missing distfile PyQt-mac-gpl-4.11.1.tar.gz
        Package xservers: missing distfile xservers-3.3.6.5.tar.bz2
        Package xview-clients: missing distfile xview3.2p1-X11R6.tar.gz
        Package xview-lib: missing distfile xview3.2p1-X11R6.tar.gz

Otherwise, existing SHA1 digests verified and found to be the same on
the machine holding the existing distfiles (morden).  All existing
SHA1 digests retained for now as an audit trail.

Log message:
Add builtin.mk.

Log message:
these should have bl3.mk

Log message:
Import dri3proto-1.0 as x11/dri3proto.

The DRI3 extension provides mechanisms to translate between direct
rendered buffers and X pixmaps. When combined with the Present
extension, a complete direct rendering solution for OpenGL is
provided.

The direct rendered buffers are passed across the protocol via
standard POSIX file descriptor passing mechanisms. On Linux, these
buffers are DMA-BUF objects.

DRI3 also includes a mechanism to translate between Linux Futexes
and X Sync extension Fences. This provides a synchronization
mechanism which can be used to serialize access to shared render
buffers.