diff --git a/xpcom/build/PoisonIOInterposer.h b/xpcom/build/PoisonIOInterposer.h
index c8009bcac400..5c488369f955 100644
--- a/xpcom/build/PoisonIOInterposer.h
+++ b/xpcom/build/PoisonIOInterposer.h
@@ -37,7 +37,7 @@ void MozillaUnRegisterDebugFILE(FILE* aFile);
 
 MOZ_END_EXTERN_C
 
-#if defined(XP_MACOSX) || (defined(XP_WIN) && !defined(__MINGW32__))
+#if defined(XP_MACOSX) || defined(XP_WIN)
 
 #  ifdef __cplusplus
 namespace mozilla {
@@ -74,7 +74,7 @@ void ClearPoisonIOInterposer();
 }  // namespace mozilla
 #  endif /* __cplusplus */
 
-#else /* defined(XP_MACOSX) || (defined(XP_WIN) && !defined(__MINGW32__)) */
+#else /* defined(XP_MACOSX) || defined(XP_WIN) */
 
 #  ifdef __cplusplus
 namespace mozilla {
diff --git a/xpcom/build/moz.build b/xpcom/build/moz.build
index 069fcbe0d111..d8674b3c29fb 100755
--- a/xpcom/build/moz.build
+++ b/xpcom/build/moz.build
@@ -30,14 +30,11 @@ if CONFIG['OS_ARCH'] == 'WINNT':
     EXPORTS.mozilla += [
         'perfprobe.h',
     ]
-    SOURCES += ['perfprobe.cpp']
-    if CONFIG['CC_TYPE'] not in ('gcc', 'clang'):
-        SOURCES += [
-            'PoisonIOInterposerBase.cpp',
-            'PoisonIOInterposerWin.cpp',
-        ]
-    else:
-        SOURCES += ['PoisonIOInterposerStub.cpp']
+    SOURCES += [
+        'perfprobe.cpp',
+        'PoisonIOInterposerBase.cpp',
+        'PoisonIOInterposerWin.cpp',
+    ]
 elif CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':
     UNIFIED_SOURCES += [
         'PoisonIOInterposerBase.cpp',