Adding `GC.compact` and compacting GC support.

This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:

  https://bugs.ruby-lang.org/issues/15626

[Feature #15626]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 6 deletions

diff --git a/symbol.c b/symbol.c
index 09fe7ecb33..a3422501a8 100644
--- a/symbol.c
+++ b/symbol.c
@@ -60,12 +60,7 @@ enum id_entry_type {
     ID_ENTRY_SIZE
 };
 
-static struct symbols {
-    rb_id_serial_t last_id;
-    st_table *str_sym;
-    VALUE ids;
-    VALUE dsymbol_fstr_hash;
-} global_symbols = {tNEXT_ID-1};
+rb_symbols_t global_symbols = {tNEXT_ID-1};
 
 static const struct st_hash_type symhash = {
     rb_str_hash_cmp,