Help copying & renaming file names

[samantha domville]

Hi - I have an include directory with many .h files. I need to create a rule 
which is a SINGLE line to loop through all *.h files in the include directory 
to 
create a HEADER list (below) instead of manually creating the list.

HEADER    +=  a.hh
HEADER    +=  b.hh
HEADER    +=  c.hh
....


So I need a foreach loop which loops through all the include/*.h files, and 
appends them with a .hh and adds them to the HEADER += .  list. Possibly 
something like this, which I will mess up but anyway:

$(foreach i, $(INCLUDE_DIR)/%.h )
    HEADER += $(@:%.h=%.hh)

please help, thanks