diff --git a/inc/ia32/efibind.h b/inc/ia32/efibind.h
index b8db581..1b11f10 100644
--- a/inc/ia32/efibind.h
+++ b/inc/ia32/efibind.h
@@ -272,7 +272,7 @@ typedef uint32_t   UINTN;
 #ifdef NO_INTERFACE_DECL
 #define INTERFACE_DECL(x)
 #else
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
 #define INTERFACE_DECL(x) struct x
 #else
 #define INTERFACE_DECL(x) typedef struct x
diff --git a/inc/ia64/efibind.h b/inc/ia64/efibind.h
index 6f9a6f7..b415461 100644
--- a/inc/ia64/efibind.h
+++ b/inc/ia64/efibind.h
@@ -219,7 +219,7 @@ void __mf (void);
 #ifdef NO_INTERFACE_DECL
 #define INTERFACE_DECL(x)
 #else
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
 #define INTERFACE_DECL(x) struct x
 #else
 #define INTERFACE_DECL(x) typedef struct x
diff --git a/inc/x86_64/efibind.h b/inc/x86_64/efibind.h
index 6bbd337..5ee620b 100644
--- a/inc/x86_64/efibind.h
+++ b/inc/x86_64/efibind.h
@@ -284,7 +284,7 @@ typedef uint64_t   UINTN;
 #ifdef NO_INTERFACE_DECL
 #define INTERFACE_DECL(x)
 #else
-#ifdef __GNUC__
+#if defined(__GNUC__) || defined(_MSC_EXTENSIONS)
 #define INTERFACE_DECL(x) struct x
 #else
 #define INTERFACE_DECL(x) typedef struct x