thep8i-2.0.1 is not configuring against pythia8-327.
The latest pythia8-327 is built with -pthread and now a test performed by AC of thep8i to check Pythia8 is failing.
configure:16407: checking if Pythia8 library and headers are present and working
configure:16420: /cvmfs/sft.cern.ch/lcg/releases/gcc/10.3.0-f5826/x86_64-centos7/bin/g++ -std=c++11 -o conftest -g -O2 -I/tmp/dkons
t/install/dev4/MCGenerators/pythia8/307/x86_64-centos7-gcc10-opt/include/Pythia8 -I/tmp/dkonst/install/dev4/MCGenerators/pythia8/307
/x86_64-centos7-gcc10-opt/include -DPYTHIA8_XMLDIR="\"\"" -Wl,-rpath -Wl,/tmp/dkonst/install/dev4/MCGenerators/pythia8/307/x86_64-c
entos7-gcc10-opt/lib -L/tmp/dkonst/install/dev4/MCGenerators/pythia8/307/x86_64-centos7-gcc10-opt/lib conftest.cpp -lpythia8 >&5
/cvmfs/sft.cern.ch/lcg/releases/binutils/2.36.1-a9696/x86_64-centos7/bin/ld: /tmp/dkonst/install/dev4/MCGenerators/pythia8/307/x86_6
4-centos7-gcc10-opt/lib/libpythia8.so: undefined reference to `pthread_create'
collect2: error: ld returned 1 exit status
configure:16420: $? = 1
configure: failed program was:
Adding -lpthread to AC LIBS in configure.ac helps but I hope that you see more elegant solution.
Kind Regards, Dmitri