For tekfwtool, you don't need anything but the command line.
You need to have Xcode installed to have the compiler and the other development tools (if you don't want to install some other tool chain for some reason).
You seem to have already installed the NI libraries for 488, which is what it will use in this case.
I think this should pretty much work:
# get a copy of the kit from github
git clone https://github.com/ragges/tektools.git
# go to the tekfwtool directory
cd tektools/tekfwtool
Then with your favourite editor, in tekfwtool.c, to include the NI headers instead, replace
#include <gpib/ib.h>
with
#include <ni4882.h>
Then it SEEMS this is the NI recommended way to compile the program (not very MacOS-/NextSTEP-ish, but...):
cc -g -fsigned-char tekfwtool.c /Library/Frameworks/NI4882.framework/Resources/ni4882.o -framework CoreFoundation -I/Library/Frameworks/NI4882.framework/Headers -o tekfwtool
You should now have a working program, check that it runs with e.g.:
./tekfwtool --help
I have not tried this myself, I'd prefer not to install all the NI cruft on my machine if I don't really need it, since they have split it into ~20 packages that all will put stuff in a bunch of places and it will be some work to get rid of it again.
For new programs, I would definitely consider PyVISA, depending on what you want to do.
Ragnar