Mark win32's pthread_exit() as NORETURN
The pthread_exit() function is not expected to return. Ever. On Windows,
we call ExitThread() whose documentation claims: "Ends the calling
thread", i.e. there is no condition in which this function simply
returns: https://msdn.microsoft.com/en-us/library/windows/desktop/ms682659
While at it, fix the return type to be void, as per
http://pubs.opengroup.org/onlinepubs/9699919799/functions/pthread_exit.html
Pointed out by Jeff King, helped by Stefan Naewe, Junio Hamano &
Johannes Sixt.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
296d673733