io.c, ruby.c: include internal/variable.h for rb_gvar_readonly_setter

Same as 053f78e13988e9253d1f207bf5e23d9505112b32.
emscripten requires a prototype declaration of rb_gvar_readonly_setter
if it is refered as a function pointer.

1 files changed, 1 insertions, 0 deletions

diff --git a/ruby.c b/ruby.c
index 2d1a437e7d..509ba61352 100644
--- a/ruby.c
+++ b/ruby.c
@@ -56,6 +56,7 @@
 #include "internal/missing.h"
 #include "internal/object.h"
 #include "internal/parse.h"
+#include "internal/variable.h"
 #include "mjit.h"
 #include "ruby/encoding.h"
 #include "ruby/thread.h"