Failed to build scheme2c: "Too many ARGUMENTS for ~s"

[cwfoo]

I tried to build scheme2c on Ubuntu 20.04:

$ make forAMD64
$ cd AMD64/
$ make port

However make port fails with this error:

make[1]: Entering directory '/home/user/scheme2c/AMD64/test'
../scsc/Xs2cc -C -g test.sc
test.sc:
*****  ***** inside ERROR FORMAT Too many ARGUMENTS for ~s 
make[1]: *** [makefile:82: test.c] Error 1
make[1]: Leaving directory '/home/user/scheme2c/AMD64/test'
make: *** [makefile:12: port] Error 2

What did I do wrong?

[natethern]

July 2025: I get the same error.