dumpfile cleanup

[Nathan Sidwell]

I wanted to add '-' as a synonym for stdout in the dumping machinery.  But this 
bit of cleanup's needed first.  We check the special stdout/stderr names in 3 
different places -- that's crying out for a worker function.  We also check 
those streams by name before determining whether to fclose.  It seems more 
straight forwards to just compare to stdin & stdout themselves.

This patch does that cleanup, and the next patch will add the '-' functionality. 
  I've been using this on the modules branch for some time now.

ok for trunk?

nathan
-- 
Nathan Sidwell
-------------- next part --------------
A non-text attachment was scrubbed...
Name: dump-1.diff
Type: text/x-patch
Size: 3603 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20180426/b3ac1969/attachment.bin>