* configure (powerpc64-*-aix[5-9].*): Match powerpc64 running aix for core file support

	* rs6000-core.c: Check for __ld_info64 if compiling 64-bit gdb.
	Added BFD64 check if we are using old core file format for 32-bit gdb.
	Set sizeof CORE_COMMONSZ appropriately in case of either new or old core file format.
	(read_hdr): Added BFD64 check for 64-bit support.
	(rs6000coff_core_p): Likewise.
	(rs6000coff_core_file_matches_executable_p): Likewise.
	(rs6000coff_core_file_failing_command): Likewise.
	(rs6000coff_core_file_failing_signal): Likewise.
	
	* rs6000-core.c: Add support for debugging core files generated by binaries in Large Memory model.
	(rs6000coff_core_p): If Large Memory Model is used, then the .data segment should start from
    BDATAORG which has been defined in the system header files.