diff --git a/generator/ruby.ml b/generator/ruby.ml
index 70337135d..06f7d58a4 100644
--- a/generator/ruby.ml
+++ b/generator/ruby.ml
@@ -41,7 +41,10 @@ let rec generate_ruby_c () =
 #include <stdlib.h>
 #include <stdint.h>
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored \"-Wstrict-prototypes\"
 #include <ruby.h>
+#pragma GCC diagnostic pop
 
 #include \"guestfs.h\"