installation issues

[Bernalms]

Now i seem to have successfully installed Curvelab with the instruction below until step 2) below:
iOS=12
My installation AND issue are reproducible with these steps:

<<<<>>>>>>>>>

download and place tar FFTW-2.1.5:

/usr/local/FFTW-2.1.5.tar.gz

tar -xzvf FFTW-2.1.5.tar.gz

./configure --with-pic --prefix= /usr/local/FFTW-2.1.5 --with-gcc=/usr/bin/gcc

make && make install

<<<<<<<ADD env var FFTW to .bash_profile>>>>>>>>>>>

cd ~

vi .bash_profile

add line: export FFTW="/usr/local/fftw-2.1.5"

:wq

source .bash_profile

<<<<<<<>>>>>>>>>>>>
download CurveLab-2.1.3.tar.gz

/usr/local/CurveLab-2.1.3.tar.gz

tar -xzvf CurveLab-2.1.3.tar.gz

<<<<<>>>>>>
cd /usr/local/CurveLab-2.1.3

vi makefile.opt

<<<<<<<<<FFTW_DIR variable>>>>>>

FFTW_DIR=/usr/local/FFTW-2.1.5

<<<<<<>>>>>>>>

INCLUDES=-I${FFTW_DIR}/fftw

<<<<<<<<<>>>>>>>

LIBS=-L${FFTW_DIR}/fftw/.libs -lfftw

:wq

<<<<<<<>>>>>>>>

cd ~

vi .bash_profile

add line:
export FDCT="/usr/local/CurveLab-2.1.3"

:wq

<<<<<<>>>>>>>>
path:
~/Documents/GitHub/PyCurvelab

cd ~/Documents/GitHub/PyCurvelab

$ python3 setup.py build install

<<<<<<<<<<>>>>>>>>

running build
running build_py
creating build
creating build/lib.macosx-10.9-x86_64-3.8
creating build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/fdct3.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/fdct2.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/init.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/test.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/CLarray.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
copying pyct/fdct.py -> build/lib.macosx-10.9-x86_64-3.8/pyct
running build_ext

building '_fdct2_wrapper' extension

swigging pyct/fdct2_wrapper.i to pyct/fdct2_wrapper_wrap.cpp
^ ^
swig -python -c++ -o pyct/fdct2_wrapper_wrap.cpp pyct/fdct2_wrapper.i
^ ^^
error: command 'swig' failed: No such file or directory