Update README.md

README.md

@@ -25,6 +25,7 @@ DCXLVI: https://www.cryptojedi.org/crypto/#dclxvi
 
 # Problems and solutions
 
+On ArchLinux OS, with gcc version 7.1.1, we met the following situation:
 - Hello, I have linker error messages after typing make. What can I do?
 - Hello, you can 1) install gcc5, 2) replace g++ by g++-5 in /src/Makefile and 3) type make again.