(mostly for includes) separate from direct dependencies (so that ${.ALLSRC}
can be used to find full paths to the sources for the direct dependencies
only). The `::' hack just forgot the indirect dependendencies. This
broke building doc/usd/13.viref with `make -jN' - the index got corrupted
by being built twice concurrently.
Cleaned up the ${DFILE} rule. There was a .else clause with dead code in
it following a .else clause (make accepts this bad syntax). ${.ALLSRC}
now works in the USE_SOELIMPP case. Some client Makefiles no longer need
the SRCDIR=${.OBJDIR} hack.
0b7162ffcc