Done. I did a totally clean build. This time I get warned that ftello and fseeko are implicitly defined, then a link error when it tries to complete the building of the .dll for base. Please test on windows if you can do so and fix the error. Here is what I am getting now:
Compiling file GSFFIInvocation.m ...
Linking library libgnustep-base ...
Creating library file: ./obj/libgnustep-base.dll.a
obj/libgnustep-base.obj/NSData.m.o: In function `readContentsOfFile':
C:\GNUstep\msys\1.0\home\gregc_000\Development\gnustep\core\base\Source/NSData.m
:181: undefined reference to `fseeko'
C:\GNUstep\msys\1.0\home\gregc_000\Development\gnustep\core\base\Source/NSData.m
:193: undefined reference to `ftello'
C:\GNUstep\msys\1.0\home\gregc_000\Development\gnustep\core\base\Source/NSData.m
:204: undefined reference to `fseeko'
collect2: ld returned 1 exit status
make[4]: *** [obj/libgnustep-base.dll.a] Error 1