* configure.in: Allow enable_threads_flag value of "aix".  Define
	thread_file as "aix" for AIX 4.3 and above..
	* configure: Regenerated.

	* gthr-aix.h: New file.

	* rs6000/t-aix43: Replace soft-float multilib with pthread.
	Remove 403 processor multilib match.  Fix rios2 processor multilib
	match.

	* rs6000/aix.h (ASM_DECLARE_FUNCTION_NAME): Use function_section
	to return to appropriate csect.

From-SVN: r36541