Add rb_gc_mark_movable C-API function

Author: andrykonchin

CHANGELOG.md

@@ -9,6 +9,7 @@ Bug fixes:
 Compatibility:
 
 * Add `Exception#detailed_message` method (#3257, @andrykonchin).
+* Add `rb_gc_mark_movable` function (@andrykonchin).
 
 Performance:
 

lib/cext/ABI_version.txt

@@ -1 +1 @@
-1
+2

src/main/c/cext/gc.c

@@ -34,6 +34,10 @@ void rb_gc_mark(VALUE ptr) {
   polyglot_invoke(RUBY_CEXT, "rb_gc_mark", ptr);
 }
 
+void rb_gc_mark_movable(VALUE obj) {
+  rb_gc_mark(obj);
+}
+
 void rb_gc_mark_maybe(VALUE ptr) {
   if (!RB_TYPE_P(ptr, T_NONE)) {
     polyglot_invoke(RUBY_CEXT, "rb_gc_mark", ptr);

src/main/java/org/truffleruby/core/MarkingService.java

@@ -27,9 +27,9 @@
  * Since we are not running on a VM that allows us to add custom mark functions to our garbage collector we keep objects
  * alive in 2 ways. Any object converted to a native handle can be kept alive by executing a
  * {@link MarkingServiceNodes.KeepAliveNode}. This will add the object to two lists, a list of all objects converted to
- * native during this call to a C extension function which will be popped when the we return to Ruby code, and a fixed
- * sized list of objects converted to native handles. When the latter of these two lists is full all mark functions will
- * be run the next time an object is added.
+ * native during this call to a C extension function which will be popped when we return to Ruby code, and a fixed-sized
+ * list of objects converted to native handles. When the latter of these two lists is full all mark functions will be
+ * run the next time an object is added.
  *
  * Marker references only keep a week reference to their owning object to ensure they don't themselves stop the object
  * from being garbage collected. */