I recently ran into that error. My system is using centOS-6, with gcc installed. but I was unable to pip install / or install scipy from source. I checked on internet, many suggested to install gcc, but my system already had gcc and a gfotran compiler.
I finally fixed it by myself, just add a post, if can help anyone:
To fix this error on centOS-6:
error: library dfftpack has Fortran sources but no Fortran compiler found
Just yum install “gcc-gfortran.x86_64 : Fortran support”
sudo yum install gcc-gfortran.x86_64
That’s it! pretty simple 😉