https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77593
--- Comment #9 from Jerry DeLisle <jvdelisle at gcc dot gnu.org> --- (In reply to tprince from comment #8) > I show my configure parameters in my test results posts. At some time in > the past, each of them has been important. I don't know if the parameters > quoted by cygwin release pertain to cross compiling. As the parameters I > use have been successful again last week on win8.1 I don't see how they > might pertain to the f951 bootstrap failure on win10. When I get back to > the win10 box I will compare with disable bootstrap. Tim, using your parameters I was able to build. I proceeded to do a regression hunt and confirmed that it was at the DTIO patch on 8/31/2016. In this patch we added two new functions to libgfortran and set the symbol versioning. I modified the library by inserting a printf("ping\n") in the code path for a simple program. print *, "hello" end The ping does not show which means the wrong library is being used at run time. I am trying various config and bath settings to see if I can sort it out. No luck so far.