C++ compilability - don't define types inside others

The following is legal code in both C and C++:

  struct foo {
    struct bar { int a } x;
    int y;
  };

...however in C++ it defines a type called "foo::bar" instead of "bar".
Just avoid this construct altogether

1 files changed, 6 insertions, 4 deletions

diff --git a/src/gc.h b/src/gc.h
index 0a4bc1c51..fea761d1b 100644
--- a/src/gc.h
+++ b/src/gc.h
@@ -11,12 +11,14 @@
 extern "C" {
 #endif
 
+struct free_obj {
+  MRUBY_OBJECT_HEADER;
+  struct RBasic *next;
+};
+
 typedef struct {
   union {
-    struct free_obj {
-      MRUBY_OBJECT_HEADER;
-      struct RBasic *next;
-    } free;
+    struct free_obj free;
     struct RBasic basic;
     struct RObject object;
     struct RClass klass;