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@67576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 4 insertions, 0 deletions

diff --git a/gc.h b/gc.h
index 2c91e06620..727890181a 100644
--- a/gc.h
+++ b/gc.h
@@ -57,6 +57,10 @@ rb_gc_debug_body(const char *mode, const char *msg, int st, void *ptr)
 #define RUBY_GC_INFO if(0)printf
 #endif
 
+#define RUBY_MARK_NO_PIN_UNLESS_NULL(ptr) do { \
+    VALUE markobj = (ptr); \
+    if (RTEST(markobj)) {rb_gc_mark_no_pin(markobj);} \
+} while (0)
 #define RUBY_MARK_UNLESS_NULL(ptr) do { \
     VALUE markobj = (ptr); \
     if (RTEST(markobj)) {rb_gc_mark(markobj);} \