* config/rs6000/aix.h (TARGET_OS_CPP_BUILTINS): Rename to ...
	(TARGET_OS_AIX_CPP_BUILTINS): this.  Conditionally define
	__LONGDOUBLE128.
	* config/rs6000/aix41.h (TARGET_OS_CPP_BUILTINS): Use
	TARGET_OS_AIX_CPP_BUILTINS.
	* config/rs6000/aix43.h (TARGET_OS_CPP_BUILTINS): Same.
	* config/rs6000/aix51.h (TARGET_OS_CPP_BUILTINS): Same.
	* config/rs6000/aix52.h (TARGET_OS_CPP_BUILTINS): Same.
	* config/rs6000/rs6000-c.c (rs6000_cpu_cpp_builtins): Revert
	previous change.

From-SVN: r79274