ia64-aix port from Tim Wall
        * config.gcc: Add configuration for AIX5/IA64.
        * config/ia64/aix.h: New.  AIX5/IA64-specific configuration.
        * config/ia64/crt[in].asm: New.  Generic static ctor/dtor
	support prefix/suffix code.
        * config/ia64/t-aix: New.  Makefile fragment.
        * config/ia64/unwind-aix.c: New.  Unwind table entry lookup.

From-SVN: r43958