Description
This is about building scipy 1.2 using clang/fflang combo (on FreeBSD, although this is probably not really platform-specific). numpy is version 1.16.1.
There is no gfortran anywhere on the system, yet I see -lgfortran popping up in the linking command, resulting in a linking error. If I "fake" libfortran by placing an empty libgfortran.so somewhere in a directory searched by linker, everything works.
Here is a typical part of the build log:
Fortran f77 compiler: flang -Wall -g -ffixed-form -fno-second-underscore -I/usr/local/include -fPIC -O3 -funroll-loops
Fortran f90 compiler: flang -Wall -g -fno-second-underscore -I/usr/local/include -fPIC -O3 -funroll-loops
Fortran fix compiler: flang -Wall -g -ffixed-form -fno-second-underscore -Wall -g -fno-second-underscore -I/usr/local/include -fPIC -O3 -funroll-loops
compile options: '-Ibuild/src.freebsd-12.0-RELEASE-p3-amd64-2.7/build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats -I/usr/home/dima/sage/local/lib/python2.7/site-packages/numpy/core/include -I/usr/home/dima/sage/local/include/python2.7 -c'
flang:f77: scipy/stats/mvndst.f
flang:f77: build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/mvn-f2pywrappers.f
clang-6.0: warning: argument unused during compilation: '-fno-second-underscore' [-Wunused-command-line-argument]
clang-6.0: warning: argument unused during compilation: '-fno-second-underscore' [-Wunused-command-line-argument]
/usr/local/bin/flang -Wall -g -shared -L/usr/home/dima/sage/local/lib -Wl,-rpath,/usr/home/dima/sage/local/lib -L/usr/local/lib -lexecinfo build/temp.freebsd-12.0-RELEASE-p3-amd64-2.7/build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/mvnmodule.o build/temp.freebsd-12.0-RELEASE-p3-amd64-2.7/build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/fortranobject.o build/temp.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/mvndst.o build/temp.freebsd-12.0-RELEASE-p3-amd64-2.7/build/src.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/mvn-f2pywrappers.o -L/usr/lib -L/usr/home/dima/sage/local/lib -Lbuild/temp.freebsd-12.0-RELEASE-p3-amd64-2.7 -lpython2.7 -lgfortran -o build/lib.freebsd-12.0-RELEASE-p3-amd64-2.7/scipy/stats/mvn.so
Notice -lgfortran near the end of the last line above.
I don't know where it comes from.