diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index 3e9821527c..8ae4cd5b2e 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -20,6 +20,10 @@
 #include <sys/fcntl.h>
 #endif
 
+#ifndef RB_INTEGER_TYPE_P
+# define RB_INTEGER_TYPE_P(c) (FIXNUM_P(c) || RB_TYPE_P(c, T_BIGNUM))
+#endif
+
 struct StringIO {
     VALUE string;
     rb_encoding *enc;
diff --git a/version.h b/version.h
index 88676af2d9..b677ea3e30 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.3.3"
 #define RUBY_RELEASE_DATE "2017-03-28"
-#define RUBY_PATCHLEVEL 274
+#define RUBY_PATCHLEVEL 275
 
 #define RUBY_RELEASE_YEAR 2017
 #define RUBY_RELEASE_MONTH 3