OpenBLAS : /usr/bin/ld: cannot find -lgfortran

✗ gfortran --version
GNU Fortran (Ubuntu 5.5.0-12ubuntu1~16.04) 5.5.0 20171010
Copyright (C) 2015 Free Software Foundation, Inc.

GNU Fortran comes with NO WARRANTY, to the extent permitted by law.
You may redistribute copies of GNU Fortran
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING

✗ gcc --version
gcc (Ubuntu 4.8.5-4ubuntu2) 4.8.5
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

✗ g++ --version
g++ (Ubuntu 6.5.0-2ubuntu1~16.04) 6.5.0 20181026
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

https://github.com/JuliaLang/julia/issues/6150 참고

✗ gfortran -print-file-name=libgfortran.so
/usr/lib/gcc/x86_64-linux-gnu/5/libgfortran.so

make LDFLAGS=-L/usr/lib/gcc/x86_64-linux-gnu/5/ -j8