Added compiler version 7.1.0 before 6.2.0, just in case CAEN and autograder...

Added compiler version 7.1.0 before 6.2.0, just in case CAEN and autograder don't both have the same version available.  If both exist, should default to 7.1.0 (the first one in each path variable).

Makefile

@@ -17,10 +17,10 @@
 #   3. Files you want to include in your final submission cannot match the
 #      test*.cpp pattern.
 
-# enables c++17 on CAEN
-PATH := /usr/um/gcc-6.2.0/bin:$(PATH)
-LD_LIBRARY_PATH := /usr/um/gcc-6.2.0/lib64
-LD_RUN_PATH := /usr/um/gcc-6.2.0/lib64
+# enables c++17 on CAEN or 281 autograder
+PATH := /usr/um/gcc-7.1.0/bin:/usr/um/gcc-6.2.0/bin:$(PATH)
+LD_LIBRARY_PATH := /usr/um/gcc-7.1.0/lib64:/usr/um/gcc-6.2.0/lib64
+LD_RUN_PATH := /usr/um/gcc-7.1.0/lib64:/usr/um/gcc-6.2.0/lib64
 
 # This is the path from the CAEN home folder to where projects will be
 # uploaded. (eg. /home/mmdarden/eecs281/project1)