* config/rs6000/aix53.h: New file.
        * config/rs6000/aix{41,43,51,52}.h (TARGET_ALTIVEC): Define to 0.
        (TARGET_ALTIVEC_ABI): Same.
        * config/rs6000/aix.h (TARGET_ALTIVEC): Delete.
        (TARGET_ALTIVEC_ABI): Delete.
        * config.gcc (powerpc-ibm-aix5*): Rename to aix5.2.  Add new
        stanza defaulting to aix5.3.

From-SVN: r129285