Add native Windows build of meshtasticd (#11031)

src/mesh/HardwareRNG.cpp

@@ -22,6 +22,12 @@ extern Adafruit_nRFCrypto nRFCrypto;
 #include <unistd.h>
 #ifdef __linux__
 #include <sys/random.h> // getrandom()
+#elif defined(_WIN32)
+// Order is load-bearing, hence the blank line: bcrypt.h uses LONG/ULONG from
+// windows.h and does not include it itself.
+#include <windows.h>
+
+#include <bcrypt.h> // BCryptGenRandom()
 #else
 #include <stdlib.h> // arc4random_buf() on Darwin/BSD
 #endif
@@ -128,6 +134,12 @@ bool fill(uint8_t *buffer, size_t length, bool useRadioEntropy)
     if (generated == static_cast<ssize_t>(length)) {
         filled = true;
     }
+#elif defined(_WIN32)
+    // No getrandom/arc4random on Windows; BCryptGenRandom is the documented CSPRNG.
+    // Preferred over std::random_device, whose libstdc++ Windows backend reports entropy() == 0.
+    if (BCryptGenRandom(NULL, buffer, static_cast<ULONG>(length), BCRYPT_USE_SYSTEM_PREFERRED_RNG) == 0) { // STATUS_SUCCESS
+        filled = true;
+    }
 #elif defined(__EMSCRIPTEN__)
     // Browser/wasm: no getrandom/arc4random - fall through to std::random_device,
     // which emscripten backs with crypto.getRandomValues().