Add EFLAGS and THREAD_ENVIRONMENT_BLOCK for amd64

sdk/xtdk/amd64/xtstruct.h

@@ -35,5 +35,6 @@ typedef struct _KSPECIAL_REGISTERS KSPECIAL_REGISTERS, *PKSPECIAL_REGISTERS;
 typedef struct _KSWITCH_FRAME KSWITCH_FRAME, *PKSWITCH_FRAME;
 typedef struct _KTRAP_FRAME KTRAP_FRAME, *PKTRAP_FRAME;
 typedef struct _KTSS KTSS, *PKTSS;
+typedef struct _THREAD_ENVIRONMENT_BLOCK THREAD_ENVIRONMENT_BLOCK, *PTHREAD_ENVIRONMENT_BLOCK;
 
 #endif /* __XTDK_AMD64_XTSTRUCT_H */