Fix profiler error() definition and usage

Fix profiler error() definition and usage

Minor updates to profiler and gmondump, which share some code:
- fix operation of error() so it actually works as intended
- resize 4K-size auto buffer reservations to BUFSIZ (==1K)
- remove trailing '\n' from 2nd arg on error() calls everywhere
- provide consistent annotation of Windows error number displays

Fixes: 9887fb27f6126 ("Cygwin: New tool: profiler")
Fixes: 087a3d76d7335 ("Cygwin: New tool: gmondump")
Signed-off-by: Mark Geisert <mark@maxrnd.com>