Update Makefile.ligosoftware_gcc_deps: enabling gcc 7 for psu-ics

gstlal-inspiral/share/O3/optimized/Makefile.ligosoftware_gcc_deps

@@ -124,7 +124,8 @@ deps_env.sh :
 	elif [[ ${CLUSTER} == *"nemo.uwm.edu" ]] ; then \
 		echo "source ${ICC_UWM} intel64" >> $@ ; \
 		echo 'LDFLAGS_INTEL="$${GCCLDMKLFLAGS}"' >> $@ ; \
-        elif [[ ${CLUSTER} == *"psu.edu" ]] ; then \
+    elif [[ ${CLUSTER} == *"psu.edu" ]] ; then \
+        echo "source /opt/rh/devtoolset-7/enable" >> $@ ; \
 		echo "source ${ICC_PSU} intel64" >> $@ ; \
 		echo 'export LIBRARY_PATH=$${LD_LIBRARY_PATH}' >> $@ ; \
 		echo 'LDFLAGS_INTEL="$${GCCLDMKLFLAGS}"' >> $@ ; \