diff --git a/reactos/include/ndk/rtltypes.h b/reactos/include/ndk/rtltypes.h
index 4f1e5338da1..9aa41d95e5e 100644
--- a/reactos/include/ndk/rtltypes.h
+++ b/reactos/include/ndk/rtltypes.h
@@ -138,7 +138,7 @@ Author:
      HEAP_CREATE_ALIGN_16           |                       \
      HEAP_CREATE_ENABLE_TRACING     |                       \
      HEAP_CREATE_ENABLE_EXECUTE)
-#ifndef __GNUC__
+#ifdef C_ASSERT
 C_ASSERT(HEAP_CREATE_VALID_MASK == 0x0007F0FF);
 #endif
 
diff --git a/reactos/include/psdk/winnt.h b/reactos/include/psdk/winnt.h
index 712ff6f5ce4..a6cc9fb52f7 100644
--- a/reactos/include/psdk/winnt.h
+++ b/reactos/include/psdk/winnt.h
@@ -963,6 +963,7 @@ typedef enum
 #define HEAP_DISABLE_COALESCE_ON_FREE 128
 #define HEAP_CREATE_ALIGN_16 0x10000
 #define HEAP_CREATE_ENABLE_TRACING 0x20000
+#define HEAP_CREATE_ENABLE_EXECUTE 0x00040000
 #define HEAP_MAXIMUM_TAG 0xFFF
 #define HEAP_PSEUDO_TAG_FLAG 0x8000
 #define HEAP_TAG_SHIFT 16