If check off64_t fail, what will happen?

when installing geant4.10.6.p01,at the progress of cmake ,i find that terminal reveals ‘check the size off64_t --fail’ though configuring done and generating done.it seems not to have impact on installation ,but i want to ask whether this failure will lead to some terrible result or not in use?

This is a check performed on system capabilities, and simply adapts if the build for cases where the capability is, or is not, present (as is the case here). The CMake system will error out if the build cannot be configured for any reason.