Currently, known_architectures/linux only looks at the first line of '$F77 --version' to determine the version of a gnu-type fortran compiler. However, on bluewaters this returns
/opt/cray/xt-asyncpe/5.16/bin/ftn: INFO: Compiling with CRAYPE_COMPILE_TARGET=native. GNU Fortran (GCC) 4.7.2 20120920 (Cray Inc.) Copyright (C) 2012 Free Software Foundation, Inc.
The information the script is actually interested in is on the second line, not the first. Thus, I propose the attached patch (grepping for "GNU" before choosing the first line). I didn't find a problem with this patch on other machines, but there might be in case $F77 --version does not contain GNU in the line with the version.