Free environ when RUBY_FREE_AT_EXIT

The environ is malloc'd, so it gets reported as a memory leak. This
commit adds ruby_free_proctitle which frees it during shutdown when
RUBY_FREE_AT_EXIT is set.

    STACK OF 1 INSTANCE OF 'ROOT LEAK: <calloc in ruby_init_setproctitle>':
    5   dyld                                  0x18b7090e0 start + 2360
    4   ruby                                  0x10000e3a8 main + 100  main.c:58
    3   ruby                                  0x1000b4dfc ruby_options + 180  eval.c:121
    2   ruby                                  0x1001c5f70 ruby_process_options + 200  ruby.c:3014
    1   ruby                                  0x10035c9fc ruby_init_setproctitle + 76  setproctitle.c:105
    0   libsystem_malloc.dylib                0x18b8c7b78 _malloc_zone_calloc_instrumented_or_legacy + 100

1 files changed, 5 insertions, 0 deletions

diff --git a/vm.c b/vm.c
index 257c517b43..37d631116a 100644
--- a/vm.c
+++ b/vm.c
@@ -20,6 +20,7 @@
 #include "internal/eval.h"
 #include "internal/gc.h"
 #include "internal/inits.h"
+#include "internal/missing.h"
 #include "internal/object.h"
 #include "internal/proc.h"
 #include "internal/re.h"
@@ -3034,6 +3035,10 @@ ruby_vm_destruct(rb_vm_t *vm)
                 xfree(th->nt);
                 th->nt = NULL;
             }
+
+#ifndef HAVE_SETPROCTITLE
+            ruby_free_proctitle();
+#endif
         }
         else {
             if (th) {