Merge bitcoin/bitcoin#29774: build: Enable fuzz binary in MSVC

18fd522ca9 ci, msvc: Add "Run fuzz binaries" step (Hennadii Stepanov)
52933d7283 fuzz: Pass `SystemRoot` environment variable to subprocess (Hennadii Stepanov)
23cb8207cd ci, msvc: Add "Clone fuzz corpus" step (Hennadii Stepanov)
19dceddf4b build, msvc: Build `fuzz.exe` binary (Hennadii Stepanov)
4c078d7bd2 build, msvc: Enable preprocessor conformance mode (Hennadii Stepanov)
09f5a74198 fuzz: Re-implement `read_stdin` in portable way (Hennadii Stepanov)

Pull request description:

  Closes https://github.com/bitcoin/bitcoin/issues/29760.

  Suggested in https://github.com/bitcoin/bitcoin/pull/29758#issuecomment-2025593572.

ACKs for top commit:
  maflcko:
    lgtm ACK 18fd522ca9 🔍
  sipsorcery:
    tACK 18fd522ca9
  sipa:
    utACK 18fd522ca9

Tree-SHA512: 672ed6926ee9091f68f13780e77b60fc1d48731f16e847d849374f8426ffe1dafd9bcab06a27af62e8052ba345bb57f20f40579d6be8540c12ef85c23a6eec8b

src/test/fuzz/addition_overflow.cpp

@@ -24,12 +24,14 @@ void TestAdditionOverflow(FuzzedDataProvider& fuzzed_data_provider)
     assert(is_addition_overflow_custom == AdditionOverflow(j, i));
     assert(maybe_add == CheckedAdd(j, i));
     assert(sat_add == SaturatingAdd(j, i));
+#ifndef _MSC_VER
     T result_builtin;
     const bool is_addition_overflow_builtin = __builtin_add_overflow(i, j, &result_builtin);
     assert(is_addition_overflow_custom == is_addition_overflow_builtin);
     if (!is_addition_overflow_custom) {
         assert(i + j == result_builtin);
     }
+#endif
     if (is_addition_overflow_custom) {
         assert(sat_add == std::numeric_limits<T>::min() || sat_add == std::numeric_limits<T>::max());
     } else {

src/test/fuzz/deserialize.cpp

@@ -33,7 +33,6 @@
 #include <optional>
 #include <stdexcept>
 #include <stdint.h>
-#include <unistd.h>
 
 using node::SnapshotMetadata;
 

src/test/fuzz/fuzz.cpp

@@ -25,7 +25,6 @@
 #include <memory>
 #include <string>
 #include <tuple>
-#include <unistd.h>
 #include <utility>
 #include <vector>
 
@@ -135,9 +134,9 @@ void initialize()
 #if defined(PROVIDE_FUZZ_MAIN_FUNCTION)
 static bool read_stdin(std::vector<uint8_t>& data)
 {
-    uint8_t buffer[1024];
-    ssize_t length = 0;
-    while ((length = read(STDIN_FILENO, buffer, 1024)) > 0) {
+    std::istream::char_type buffer[1024];
+    std::streamsize length;
+    while ((std::cin.read(buffer, 1024), length = std::cin.gcount()) > 0) {
         data.insert(data.end(), buffer, buffer + length);
     }
     return length == 0;

src/test/fuzz/multiplication_overflow.cpp

@@ -17,12 +17,18 @@ void TestMultiplicationOverflow(FuzzedDataProvider& fuzzed_data_provider)
     const T i = fuzzed_data_provider.ConsumeIntegral<T>();
     const T j = fuzzed_data_provider.ConsumeIntegral<T>();
     const bool is_multiplication_overflow_custom = MultiplicationOverflow(i, j);
+#ifndef _MSC_VER
     T result_builtin;
     const bool is_multiplication_overflow_builtin = __builtin_mul_overflow(i, j, &result_builtin);
     assert(is_multiplication_overflow_custom == is_multiplication_overflow_builtin);
     if (!is_multiplication_overflow_custom) {
         assert(i * j == result_builtin);
     }
+#else
+    if (!is_multiplication_overflow_custom) {
+        (void)(i * j);
+    }
+#endif
 }
 } // namespace