Hi Alvaro,
If you are using Centos7, you are indeed out of luck. The system compiler is unfortunately really bad. Among other problems, the std::regex is completely broken.
You can move to a ROOT version that’s been compiled with a decent compiler, though. By setting up an LCG view from cvmfs, you can work with any compiler/operating system from this list:
ls -l /cvmfs/sft.cern.ch/lcg/views/LCG_96/
x86_64-centos7-clang8-dbg
x86_64-centos7-clang8-opt
x86_64-centos7-gcc62-opt
x86_64-centos7-gcc8-dbg
x86_64-centos7-gcc8-opt
x86_64-slc6-gcc8-opt
x86_64-ubuntu1804-gcc8-dbg
x86_64-ubuntu1804-gcc8-opt
Just source the setup.sh script from the respective directory.