using realpath/abspath in 3.81

Dear list,

I've noticed that both realpath and abspath functions take only relative 
paths as their arguments. With absolute path they break it, trying to make 
it absolute:

$ make --version
GNU Make 3.81
...
$ make -f -
$(info $(realpath d:/temp))
^Z
c:/progs/cygwin/home/nosek/d:/temp

I've tried it with:
  * Cygwin's make,
  * GnuWin32 binary release make,
  * make.exe built with MSVC++ from 3.81 sources.

I don't know if it's a win32 specific problem, or a general make 3.81 
"feature" (or just lack of feature).

Thanks for any help,
Krzysztof Nosek