--- a/gcc/config/rs6000/aix.h	Fri Oct 27 22:46:09 2017 +0900
+++ b/gcc/config/rs6000/aix.h	Thu Oct 25 07:37:49 2018 +0900
@@ -1,6 +1,6 @@
 /* Definitions of target machine for GNU compiler,
    for IBM RS/6000 POWER running AIX.
-   Copyright (C) 2000-2017 Free Software Foundation, Inc.
+   Copyright (C) 2000-2018 Free Software Foundation, Inc.
 
    This file is part of GCC.
 
@@ -23,6 +23,9 @@
 #undef  TARGET_AIX
 #define TARGET_AIX 1
 
+/* System headers are not C++-aware.  */
+#define SYSTEM_IMPLICIT_EXTERN_C 1
+
 /* Linux64.h wants to redefine TARGET_AIX based on -m64, but it can't be used
    in the #if conditional in options-default.h, so provide another macro.  */
 #undef  TARGET_AIX_OS
@@ -71,7 +74,8 @@
    `emit-rtl.c').  */
 #undef STACK_DYNAMIC_OFFSET
 #define STACK_DYNAMIC_OFFSET(FUNDECL)					\
-   RS6000_ALIGN (crtl->outgoing_args_size + STACK_POINTER_OFFSET, 16)
+   RS6000_ALIGN (crtl->outgoing_args_size.to_constant ()		\
+		 + STACK_POINTER_OFFSET, 16)
 
 #undef  TARGET_IEEEQUAD
 #define TARGET_IEEEQUAD 0