/in/foo.c:1:1: warning: data definition has no type or storage class
 gbs [] = 1
 ^~~
/in/foo.c:1:1: warning: type defaults to 'int' in declaration of 'gbs' [-Wimplicit-int]
/in/foo.c:1:10: error: invalid initializer
 gbs [] = 1
          ^
/in/foo.c:2:1: error: expected ',' or ';' before 'gbs'
 gbs (x:xs) = lcm x $ gbs xs
 ^~~