Merge bitcoin/bitcoin#26950: cleanse: switch to SecureZeroMemory for Windows cross-compile

c399c80 cleanse: Use SecureZeroMemory for mingw-w64 (release) builds (fanquake)

Pull request description:

  This PR switches our Windows release builds to use the [`SecureZeroMemory()`](https://learn.microsoft.com/en-us/previous-versions/windows/desktop/legacy/aa366877(v=vs.85)) provided by mingw-w64.

ACKs for top commit:
  sipa:
    utACK c399c80
  TheCharlatan:
    ACK c399c80

Tree-SHA512: dbb20b16c85061d2f9408a3cf69cecc16765f8f61b25a1707146767b664c7ad0caf36975380814ef8e7c49a30199daebac6d5d7a3585354d1adac8e9770199c6

Author: fanquake

src/support/cleanse.cpp

@@ -7,14 +7,14 @@
 
 #include <cstring>
 
-#if defined(_MSC_VER)
-#include <Windows.h> // For SecureZeroMemory.
+#if defined(WIN32)
+#include <windows.h>
 #endif
 
 void memory_cleanse(void *ptr, size_t len)
 {
-#if defined(_MSC_VER)
-    /* SecureZeroMemory is guaranteed not to be optimized out by MSVC. */
+#if defined(WIN32)
+    /* SecureZeroMemory is guaranteed not to be optimized out. */
     SecureZeroMemory(ptr, len);
 #else
     std::memset(ptr, 0, len);