The version of make on Tru64 5.1 has a special form $(VAR/foo/bar)  
for certain kinds of substitutions, and apparently its parser rejects  
the reference $(DEPTARGETS_._../..) that comes up in some of our  
generated Makefiles, used as a scheme for automating per-directory  
processing when we generate multiple Makefiles from one config.status  
script.  This comes from using $ 
(DEPTARGETS_@srcdir@_@CONFIG_RELTOPDIR@) in config/post.in, when  
running configure in the source tree.

It may be that $(SUBDIRS_@srcdir@) is going to have the same problem.

Workaround: Use GNU make.