more robust get_compiler_info

[Andrew Cagney]

Michael, just a thought.

Rather than having all of:
> + 	set compiler_info
> + 	set gcc_compiled
> + 	set hp_cc_compiler
> + 	set hp_ACC_compiler

inside the file that is put CC, can instead just compiler_info be set. 
The rest can then be set using that value.  It would, if nothing else, 
let us more quickly know if compiler_info isn't correct.

Andrew