diff --git a/sys/unix/Makefile.src b/sys/unix/Makefile.src
index 16d087472..7b477940f 100644
--- a/sys/unix/Makefile.src
+++ b/sys/unix/Makefile.src
@@ -1,5 +1,5 @@
 #	NetHack Makefile.
-# NetHack 3.6  Makefile.src	$NHDT-Date: 1447313972 2015/11/12 07:39:32 $  $NHDT-Branch: master $:$NHDT-Revision: 1.45 $
+# NetHack 3.6  Makefile.src	$NHDT-Date: 1459122529 2016/03/27 23:48:49 $  $NHDT-Branch: NetHack-3.6.0 $:$NHDT-Revision: 1.46 $
 
 # Root of source tree:
 NHSROOT=..
@@ -357,9 +357,9 @@ WINCSRC = $(WINTTYSRC) $(WINX11SRC) $(WINGNOMESRC) $(WINGEMSRC)
 WINCXXSRC = $(WINQTSRC) $(WINBESRC)
 
 # Files for window system chaining.  Requires SYSCF; include via HINTSRC/HINTOBJ
-CHAINSRC=../win/chain/wc_chainin.c ../win/chain/wc_chainout.c \
-	../win/chain/wc_trace.c
-CHAINOBJ=wc_chainin.o wc_chainout.o wc_trace.o
+CHAINSRC = ../win/chain/wc_chainin.c ../win/chain/wc_chainout.c \
+	   ../win/chain/wc_trace.c
+CHAINOBJ = wc_chainin.o wc_chainout.o wc_trace.o
 
 # .c files for this version (for date.h)
 VERSOURCES = $(HACKCSRC) $(SYSSRC) $(WINSRC) $(CHAINSRC) $(GENCSRC)
@@ -378,9 +378,9 @@ HACKINCL = align.h amiconf.h artifact.h artilist.h attrib.h beconf.h botl.h \
 	global.h hack.h lev.h lint.h macconf.h mextra.h mfndpos.h micro.h \
 	mkroom.h \
 	monattk.h mondata.h monflag.h monst.h monsym.h obj.h objclass.h \
-	os2conf.h patchlevel.h pcconf.h permonst.h prop.h rect.h region.h rm.h \
-	sp_lev.h spell.h sys.h system.h tcap.h timeout.h tosconf.h tradstdc.h \
-	trampoli.h trap.h unixconf.h vision.h vmsconf.h wintty.h \
+	os2conf.h patchlevel.h pcconf.h permonst.h prop.h rect.h region.h \
+	rm.h sp_lev.h spell.h sys.h system.h tcap.h timeout.h tosconf.h \
+	tradstdc.h trampoli.h trap.h unixconf.h vision.h vmsconf.h wintty.h \
 	winX.h winprocs.h wintype.h you.h youprop.h
 
 HSOURCES = $(HACKINCL) date.h onames.h pm.h vis_tab.h\
@@ -490,23 +490,31 @@ qt_win.moc: ../include/qt_win.h
 qttableview.moc: ../include/qttableview.h
 	$(QTDIR)/bin/moc -o qttableview.moc ../include/qttableview.h
 
-$(MAKEDEFS): ../util/makedefs.c  $(CONFIG_H) ../include/permonst.h \
+#	build monst.o and objects.o before executing '$(MAKE) makedefs'
+$(MAKEDEFS): $(FIRSTOBJ) \
+		../util/makedefs.c $(CONFIG_H) ../include/permonst.h \
 		../include/objclass.h ../include/monsym.h \
 		../include/artilist.h ../include/dungeon.h ../include/obj.h \
 		../include/monst.h ../include/you.h ../include/flag.h \
 		../include/dlb.h ../include/patchlevel.h ../include/qtext.h
-	@( cd ../util ; $(MAKE) makedefs)
+	@( cd ../util ; $(MAKE) makedefs )
 
+#	Source files created by 'makedefs' at build time.
+#	Each is given an artificial dependency upon the one before
+#	so that parallel makes will have to build them sequentially and
+#	not clobber makedefs by attempting simultaneous builds of it.
 ../include/onames.h: $(MAKEDEFS)
 	@( cd ../util ; $(MAKE) ../include/onames.h )
-../include/pm.h: $(MAKEDEFS)
+../include/pm.h: $(MAKEDEFS) ../include/onames.h
 	@( cd ../util ; $(MAKE) ../include/pm.h )
-monstr.c: $(MAKEDEFS)
+monstr.c: $(MAKEDEFS) ../include/pm.h
 	@( cd ../util ; $(MAKE) ../src/monstr.c )
-../include/vis_tab.h: $(MAKEDEFS)
+../include/vis_tab.h: $(MAKEDEFS) monstr.c
 	@( cd ../util ; $(MAKE) ../include/vis_tab.h )
 # makedefs -z makes both vis_tab.h and vis_tab.c, but writes the .h first
 vis_tab.c: ../include/vis_tab.h
+#	Created at build time for configurations which support tiles,
+#	but not by makedefs so not connected to the others.
 tile.c: ../win/share/tilemap.c $(HACK_H)
 	@( cd ../util ; $(MAKE) ../src/tile.c )