Fix disabling of automatic dynamic libraries registration

(a cherry-pick of commit 0d19067c3 from 'master')

Now, if GC_no_dls then GC_is_visible does not cause registration of
dynamic libraries.

* ptr_chck.c [!THREADS && (DYNAMIC_LOADING || MSWIN32 || MSWINCE
|| CYGWIN32 || PCR)] (GC_is_visible): Do not call
GC_register_dynamic_libraries() followed by GC_is_static_root()
if GC_no_dls.

1 files changed, 4 insertions, 3 deletions

diff --git a/ptr_chck.c b/ptr_chck.c
index 687aabe6..716336a4 100644
--- a/ptr_chck.c
+++ b/ptr_chck.c
@@ -207,9 +207,10 @@ GC_API void * GC_CALL GC_is_visible(void *p)
             /* Else do it again correctly:      */
 #           if defined(DYNAMIC_LOADING) || defined(MSWIN32) \
                 || defined(MSWINCE) || defined(CYGWIN32) || defined(PCR)
-              GC_register_dynamic_libraries();
-              if (GC_is_static_root(p))
-                return(p);
+              if (!GC_no_dls) {
+                GC_register_dynamic_libraries();
+                if (GC_is_static_root(p)) return p;
+              }
 #           endif
             goto fail;
         } else {