If stdout is __gshared, why does this throw / crash?

[Marco Leise via Digitalmars-d-learn]

Got it now: https://issues.dlang.org/show_bug.cgi?id=15768

writeln() creates a copy of the stdout struct in a non
thread-safe way. If stdout has been assigned a File struct
created from a file name this copy includes a "racy"
increment/decrement of a reference count to the underlying
C-library FILE*. In the case that the reference count is
erroneously reaching 0, the file is closed prematurely and
when Glibc tries to access internal data it results in the
observable SIGSEGV.

-- 
Marco