Hi Mark,
hard to help you without additional details.
The latest Grumpfish library is 4.06 (from 1995). To recompile it from scratch, you need to compile 10 Assembler files (where heavy reworking would be required for Windows 32/64), 4 C sources (all requires reworking), and more than 100 PRG sources. Most of these .prg sources are compilable by FlagShip w/o problems, you however need to use "FlagShip -na -c *.prg" switches to get .OBJ for 32/64bit.
I have used many of Grumpfish functions (those which do nor require ASM or C files), by simply adding the correponding (recompiled) .OBJ to the FS compile/link list. I would suggest not to replace FlagShip getsys.prg (containing readmodal() etc.) by Grumpfish's, since FS fully supports all the GUI FS extensions. Also mouse functions are standard in FS.Several Grumfish UDFs are replaceable by FS2 add-on functions or by the Nanfor library. To create .LIB for 32/64bit OS, you may use the fsmake tool.
Hope this helps,
Alex