gnumake on W32 - automatic prerequisites

[mc]

I am trying to get automatic prerequisites to work on Windows NT,
using Gnumake
version 3.79.1, and MSVC++ 7.x .  I am using the compiler to produce a
preprocessor output file, and sed to reduce the dependencies listed
there into a valid makefile format, using the name convention
'whatever.d' . I wind up with a textural file like:

whatever.obj : \
    whatever.h \
    whaterver2.h \

I then include whatever.d in my makefile:

include whatever.d

which means that it is read by gnumake and incorporated into the make.
I know it is being read because if I purposefully mess up the format
of this included make file, the make dies with a correct error
diagnostic.

My problem is that the dependency relationship is apparently not being
recognized; If I touch whatever2.h, gnumake does not force a
re-compile of the whatever.obj dependent on that include file.

Anyone know what is going wrong here?

TIA...

-mike