BUG #14001: pg_ctl error output empty/faulty

The following bug has been logged on the website:

Bug reference:      14001
Logged by:          Manuel Mathar
Email address:      doublem09@googlemail.com
PostgreSQL version: 9.5.1
Operating system:   Windows 7 (Enterprise), Windows 10
Description:

Error messages from pg_ctl can't be piped. Tested for 9.5.1, 9.5.0 and 9.3.5
on Windows 7 and 10.

For a simple "pg_ctl status" an error message concerning the missing "-D"
parameter should be expected. But when reading the standard error with
another program (tested with Qt's QProcess readAllStandardError) or piping
it into a file "pg_ctl status 2> out.txt" the result is empty.

Under Windows 10 error messages don't appear even in the command line (no
problem for Windows 7 here).
E.g. typing "pg_ctl status" in a cmd shell yields no output at all.

After a brief test it seems this can be fixed by correcting the negation
"if (!pgwin32_is_service())" to "if (pgwin32_is_service())" in pg_ctl.c
write_stderr(...).

Sorry if I misunderstood this or forgot important information. Feel free to
contact me if You have further questions.

Best regards,
Manuel Mathar