XMLSEC_NO_SIZE_T is /not/ used with MSVC

...where external/libxmlsec/ExternalProject_xmlsec.mk uses win32/configure.js
instead of configure.  But that inconsistency generally got hidden on Windows by
xmlsecurity/inc/pch/precompiled_xsec_xmlsec.hxx including the raw xmlsec include
files instead of xmlsecurity/xmlsec-wrapper.h, so only gets noticed when using
--disable-pch (as is needed when building with clang-cl).

TODO: Don't know how to fix bin/update_pch so that precompiled_xsec_xmlsec.hxx
doesn't get broken again on the next update.

Change-Id: If385066a1e0f949d943aab7e9a5e969fbf0d0794

xmlsecurity/inc/pch/precompiled_xsec_xmlsec.hxx

@@ -115,17 +115,8 @@
 #include <uno/data.h>
 #include <uno/sequence2.h>
 #include <xmloff/dllapi.h>
-#include <xmlsec/base64.h>
-#include <xmlsec/bn.h>
-#include <xmlsec/errors.h>
-#include <xmlsec/io.h>
-#include <xmlsec/keysmngr.h>
-#include <xmlsec/strings.h>
-#include <xmlsec/xmldsig.h>
-#include <xmlsec/xmlenc.h>
-#include <xmlsec/xmlsec.h>
-#include <xmlsec/xmltree.h>
 #include <xmlsecurity/biginteger.hxx>
+#include <xmlsecurity/xmlsec-wrapper.h>
 
 // Cleanup windows header macro pollution.
 #if defined(_WIN32) && defined(WINAPI)

xmlsecurity/inc/xmlsecurity/xmlsec-wrapper.h

@@ -24,8 +24,8 @@
 
 #include <sal/types.h>
 
-// Cf. xmlsec's configure.in:
-#if SAL_TYPES_SIZEOFPOINTER != 4
+// Cf. xmlsec's configure.in (but which isn't used for MSVC):
+#if !defined _MSC_VER && SAL_TYPES_SIZEOFPOINTER != 4
 #define XMLSEC_NO_SIZE_T
 #endif