Build fails: undefined reference to `main'

[yurivict]

5.6.1 fails to build on FreeBSD:

/usr/local/bin/ld: /usr/lib/crt1.o: in function `_start':
/usr/src/lib/csu/amd64/crt1.c:76: undefined reference to `main'
collect2: error: ld returned 1 exit status
error: Command "/usr/local/bin/gfortran9 -Wall -g -Wl,-rpath=/usr/local/lib/gcc9 -L/usr/local/lib/gcc9 -B/usr/local/bin -fstack-protector-strong build/temp.freebsd-12.0-STABLE-amd64-3.7/build/src.freebsd-12.0-STABLE-amd64-3.7/clawpack/riemann/acoustics_1D_ptwisemodule.o build/temp.freebsd-12.0-STABLE-amd64-3.7/build/src.freebsd-12.0-STABLE-amd64-3.7/build/src.freebsd-12.0-STABLE-amd64-3.7/clawpack/riemann/fortranobject.o build/temp.freebsd-12.0-STABLE-amd64-3.7/riemann/src/rp1_ptwise.o build/temp.freebsd-12.0-STABLE-amd64-3.7/riemann/src/rp1_acoustics_ptwise.o build/temp.freebsd-12.0-STABLE-amd64-3.7/build/src.freebsd-12.0-STABLE-amd64-3.7/clawpack/riemann/acoustics_1D_ptwise-f2pywrappers.o -L/usr/local/lib/gcc9/gcc/x86_64-portbld-freebsd12.0/9.2.0 -L/usr/local/lib -lpython3.7m -lgfortran -o build/lib.freebsd-12.0-STABLE-amd64-3.7/clawpack/riemann/acoustics_1D_ptwise.so" failed with exit status 1
*** Error code 1

[mandli]

Can you provide some more info regarding the issue?

[yurivict]

I tried to build it in the FreeBSD ports framework, using python-3.7 on FreeBSD 12.

Now sure what other info can I provide.

[mandli]

It looks like one of the Fortran point-wise solvers failed to build, which I think means that it got stuck when installing the Fortran code for PyClaw. Can you post an install.log or pyclaw.log that it generated?