diff --git a/src/google/protobuf/io/coded_stream.h b/src/google/protobuf/io/coded_stream.h
index a4d5f960a33..df8c4499ad7 100644
--- a/src/google/protobuf/io/coded_stream.h
+++ b/src/google/protobuf/io/coded_stream.h
@@ -120,12 +120,12 @@
 #include <type_traits>
 #include <utility>
 
-#ifdef _MSC_VER
+#ifdef _WIN32
 // Assuming windows is always little-endian.
 #if !defined(PROTOBUF_DISABLE_LITTLE_ENDIAN_OPT_FOR_TEST)
 #define PROTOBUF_LITTLE_ENDIAN 1
 #endif
-#if _MSC_VER >= 1300 && !defined(__INTEL_COMPILER)
+#if defined(_MSC_VER) && _MSC_VER >= 1300 && !defined(__INTEL_COMPILER)
 // If MSVC has "/RTCc" set, it will complain about truncating casts at
 // runtime.  This file contains some intentional truncating casts.
 #pragma runtime_checks("c", off)
diff --git a/src/google/protobuf/port_def.inc b/src/google/protobuf/port_def.inc
index d15073a41fa..11e01601ca8 100644
--- a/src/google/protobuf/port_def.inc
+++ b/src/google/protobuf/port_def.inc
@@ -615,7 +615,7 @@
 #define PROTOBUF_PRAGMA_INIT_SEG
 #endif
 
-#if defined(__has_attribute)
+#if defined(__has_attribute) && !defined(__MINGW32__)
 #if __has_attribute(weak)
 #define PROTOBUF_ATTRIBUTE_WEAK __attribute__((weak))
 #endif