+ *) Avoid false positives in memory leak detection code (crypto/mem_dbg.c)
+ due to incorrect handling of multi-threading:
+
+ 1. Fix timing glitch in the MemCheck_off() portion of CRYPTO_mem_ctrl().
+
+ 2. Fix logical glitch in is_MemCheck_on() aka CRYPTO_is_mem_check_on().
+
+ 3. Count how many times MemCheck_off() has been called so that
+ nested use can be treated correctly. This also avoids
+ inband-signalling in the previous code (which relied on the
+ assumption that thread ID 0 is impossible).
+ [Bodo Moeller]
+