9006 parallel loader builds fail sporadically

@@ -25,11 +25,16 @@
 clobber :=      TARGET = clobber
 install :=      TARGET = install
 
 all clean clobber: $(SUBDIRS)
 
-install: all $(INSTDIRS)
+# We must use wait, rather than dependencies, as otherwise we'll run 'make
+# install' in non-INSTDIRS.
+#
+# at present, this makes no difference, if subdirs are added which are not dependencies of instdirs,
+# 'install: all' rules should be added to 'subdirs' Makefiles
+install: all .WAIT $(INSTDIRS)
 
 $(SUBDIRS): FRC
         @cd $@; pwd; $(MAKE) $(MFLAGS) $(TARGET)
 
 FRC: