diff --git a/mingw-w64-tools/widl/include/windef.h b/mingw-w64-tools/widl/include/windef.h
index b8e5ed6..5351afe 100644
--- a/mingw-w64-tools/widl/include/windef.h
+++ b/mingw-w64-tools/widl/include/windef.h
@@ -74,7 +74,7 @@
 #  endif
 # elif defined(__arm__) && defined (__GNUC__) && !defined(__SOFTFP__)
 #   define __stdcall __attribute__((pcs("aapcs-vfp")))
-# elif defined(__aarch64__) && defined (__GNUC__)
+# elif defined(__aarch64__) && defined (__GNUC__) && __has_attribute(ms_abi)
 #  define __stdcall __attribute__((ms_abi))
 # else  /* __i386__ */
 #  define __stdcall
@@ -103,7 +103,7 @@
 #endif
 
 #ifndef __ms_va_list
-# if (defined(__x86_64__) || defined(__aarch64__)) && defined (__GNUC__)
+# if (defined(__x86_64__) || (defined(__aarch64__) && __has_attribute(ms_abi))) && defined (__GNUC__)
 #  define __ms_va_list __builtin_ms_va_list
 #  define __ms_va_start(list,arg) __builtin_ms_va_start(list,arg)
 #  define __ms_va_end(list) __builtin_ms_va_end(list)
diff --git a/mingw-w64-tools/widl/include/winnt.h b/mingw-w64-tools/widl/include/winnt.h
index 04353d9..83fcc67 100644
--- a/mingw-w64-tools/widl/include/winnt.h
+++ b/mingw-w64-tools/widl/include/winnt.h
@@ -6897,7 +6897,7 @@
 #if defined(_MSC_VER)
 
 #define InterlockedCompareExchange128 _InterlockedCompareExchange128
-static inline unsigned char _InterlockedCompareExchange128(__int64 *dest, __int64 xchg_high, __int64 xchg_low, __int64 *compare);
+unsigned char _InterlockedCompareExchange128(volatile __int64 *dest, __int64 xchg_high, __int64 xchg_low, __int64 *compare);
 #pragma intrinsic(_InterlockedCompareExchange128)
 
 #elif defined(__x86_64__)