Check for truncation when converting buffer size from size_t to openssl's

int argument.

Try to fix possible thread-safety issues in SSL wrapper.


[SVN r42759]

libs/asio

@@ -1 +1 @@
-Subproject commit 08410277899e48ccce484010675ab6c0e3943ee3
+Subproject commit 1f215cd262f523d14da9eea37e7a60c462e27ce5