Building R for Windows

I have some C code (using an old Borland compiler)  that calls a DLL that 
I'd like to get working from Windows and R (so I can read ABF files -- Axon 
Binary Files -- directly in R).

I thought a good first approach would be able to build  R in Windows, so 
that's what I'm trying to do.  [I've done test builds of R under Linux 
before, and that seemed fairly simple.]

I've tried to follow the instructions "Building R for Windows" from here:
http://www.murdoch-sutherland.com/Rtools/

I installed Rtools27.exe and the other tools suggested here:
http://www.murdoch-sutherland.com/Rtools/Rtools.txt

I followed the instructions in first Rtools link "Obtaining the R source 
code" and have a directory with the latest C:\R\R-2-6-1.

Should the "Building R for Windows" document say something about what should 
be done next?

Section 2.1 Simple compilation
http://cran.r-project.org/doc/manuals/R-admin.html#The-Windows-toolset
says:

./configure
make

These two statements work find on Linux, but I must be missing something 
under Windows XP Pro?  Any suggestions?

Open a command window at R_HOME/src/gnuwin32. Edit MkRules to set the appropriate paths as needed and to set the type(s) of help that you want built. Beware: MkRules contains tabs and some editors (e.g., WinEdt) silently remove them. Then run

     make all recommended

and sit back and wait while the basic compile takes place. 

Also, what changes must be made to build R on a 64-bit Windows box?  Do R 
Tools work for a 64-bit environment?

Thanks for any help on this.

Earl F. Glynn
Bioinformatics
Stowers Institute for Medical Research