'make install-headers' is not complete

[Daniel Jacobowitz <drow at mvista dot com>]

... and hasn't been for at least eight years or so, as far as I can tell. 
At least the relevant makefile fragments haven't changed much.  The symptom
is that 'features.h' doesn't get installed.  This may be exposed by some
recent change in GNU make....

My first guess at the problem was in Makerules:

install-%:: install-%-nosubdir ;

But the rule in the Makefile:
$(+subdir_targets): %: $(addsuffix /%,$(subdirs)) 

is apparently considered a double-colon rule.  It also says that:
   Each double-colon rule should specify commands; if it does not, an
implicit rule will be used if one applies.

My best guess is that this is causing only the one set of dependencies to be
considered and that we should be using single-colon rules; I don't know how
to write the %: bit without make considering it a double-colon rule, though. 
Or it may be an outright bug in GNU make.  Anyone have a better
understanding of this than I do?

-- 
Daniel Jacobowitz                           Carnegie Mellon University
MontaVista Software                         Debian GNU/Linux Developer