This makes schan_EncryptMessage/schan_DecryptMessage thread safe between
each other.
MSDN states that it's supposed to be thread safe.
Fixes Magic The Gathering: Online crash:
https://bugs.winehq.org/show_bug.cgi?id=43453

Signed-off-by: Anton Romanov <theli.ua@gmail.com>
---
 dlls/secur32/schannel.c        | 33 +++++++++++++++++++--------------
 dlls/secur32/schannel_gnutls.c | 12 +++++++-----
 dlls/secur32/schannel_macosx.c | 21 ++++++++++++---------
 dlls/secur32/secur32_priv.h    |  5 +++--
 4 files changed, 41 insertions(+), 30 deletions(-)

diff --git a/dlls/secur32/schannel.c b/dlls/secur32/schannel.c
index 82374efd55..1f938e1a37 100644
--- a/dlls/secur32/schannel.c
+++ b/dlls/secur32/schannel.c
@@ -59,6 +59,8 @@ struct schan_context
     schan_imp_session session;
     ULONG req_ctx_attr;
     const CERT_CONTEXT *cert;
+    struct schan_transport *push_transport;
+    struct schan_transport *pull_transport;

diff --git a/dlls/secur32/schannel_gnutls.c b/dlls/secur32/schannel_gnutls.c
index bc3bbaf67d..97b2c2d767 100644
--- a/dlls/secur32/schannel_gnutls.c
+++ b/dlls/secur32/schannel_gnutls.c
@@ -73,7 +73,7 @@ MAKE_FUNCPTR(gnutls_record_send);
 MAKE_FUNCPTR(gnutls_server_name_set);
 MAKE_FUNCPTR(gnutls_transport_get_ptr);
 MAKE_FUNCPTR(gnutls_transport_set_errno);
-MAKE_FUNCPTR(gnutls_transport_set_ptr);
+MAKE_FUNCPTR(gnutls_transport_set_ptr2);