coffcode.h handle_COMDAT tidy

coffcode.h handle_COMDAT tidy

I started down the path of attempting to fix
https://sourceware.org/pipermail/binutils/2023-April/127263.html but
decided after a while that I didn't want to mess with this code..

This patch is a just a few things that I thought worth doing, the main
one being reporting of errors up the call chain.  The while loop to
for loop change is shamelessly stolen from Oleg.

	* coffcode.h (handle_COMDAT): Return bool.  Make sec_flags a
	flagword*, and adjust to suit.  Replace while loop with for
	loop.  Check isym.n_numaux before reading aux entries.  Alloc
	coff_comdat_info and name in one call to bfd_alloc.  Remove
	goto breakloop.
	(styp_to_sec_flags): Adjust handle_COMDAT call.