crypt32: Add stub for CryptSignMessage.

dlls/crypt32/crypt32.spec

diff --git a/dlls/crypt32/crypt32.spec b/dlls/crypt32/crypt32.spec
index 61e4d3d..f531bf6 100644
--- a/dlls/crypt32/crypt32.spec
+++ b/dlls/crypt32/crypt32.spec
@@ -181,7 +181,7 @@
 @ stub CryptSignAndEncryptMessage
 @ stdcall CryptSignCertificate(long long long ptr long ptr ptr ptr ptr)
 @ stub CryptSignHashU
-@ stub CryptSignMessage
+@ stdcall CryptSignMessage(ptr long long ptr ptr ptr ptr)
 @ stub CryptSignMessageWithKey
 @ stdcall CryptUnprotectData(ptr ptr ptr ptr ptr long ptr)
 @ stdcall CryptUnregisterDefaultOIDFunction(long str wstr)

dlls/crypt32/message.c

diff --git a/dlls/crypt32/message.c b/dlls/crypt32/message.c
index f06af0e..81eb913 100644
--- a/dlls/crypt32/message.c
+++ b/dlls/crypt32/message.c
@@ -415,3 +415,12 @@
     }
     return ret;
 }
+
+BOOL WINAPI CryptSignMessage(PCRYPT_SIGN_MESSAGE_PARA pSignPara,
+ BOOL fDetachedSignature, DWORD cToBeSigned, const BYTE *rgpbToBeSigned[],
+ DWORD rgcbToBeSigned[], BYTE *pbSignedBlob, DWORD *pcbSignedBlob)
+{
+    FIXME("(%p, %d, %d, %p, %p, %p, %p): stub\n", pSignPara, fDetachedSignature,
+     cToBeSigned, rgpbToBeSigned, rgcbToBeSigned, pbSignedBlob, pcbSignedBlob);
+    return FALSE;
+}