Make does not work for interfaces. Why?

Hello,

I am trying to adapt the pgeasy interface to be able to use libpg with
LabVIEW.
I got the complete cygwin-pg-sources from cygwin as well as the
binaries. The latter work well, but:

First I made some changes to the pgeasy.c and pgeasy.h and tried to
compile. But no way...:-(
Then I tried to compile the original, which did not work out either:

After /usr/src/postgresql-7.2.3-1/src/interfaces/libpgeasy/make
I just get some errors, that I cannot fix:

$ make
Makefile:11: ../../../src/Makefile.global: No such file or directory
Makefile:33: /src/Makefile.shlib:  No such file or directory
make: *** No rule to make target '/src/Makefile.shlib'. Stop.

There are only *.in files (like Makefile.global.in).

What's wrong?
How can I compile the pgeasy interface? (Knowing this I am able to
compile my changes I guess...)

I'd be very thankful for any help!!!

Jan Klostermann

PS: I have a recently downloaded cygwin with postgres and gcc, etc. on a
Win2K-System.