/in/foo.cc: In function 'int main()':
/in/foo.cc:13:5: error: unable to find numeric literal operator 'operator""x'
   y=2x-1;
     ^~
/in/foo.cc:13:5: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/in/foo.cc:17:5: error: unable to find numeric literal operator 'operator""x'
   y=3x+4;
     ^~
/in/foo.cc:17:5: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/in/foo.cc:21:8: error: unable to find numeric literal operator 'operator""x'
   y=90-5x;
        ^~
/in/foo.cc:21:8: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes
/in/foo.cc:25:8: error: unable to find numeric literal operator 'operator""x'
   y=80+3x;
        ^~
/in/foo.cc:25:8: note: use -std=gnu++11 or -fext-numeric-literals to enable more built-in suffixes