[Bug c/61846] gcc assumes errno might be negative and issues unnecessary warning

[zbyszek at in dot waw.pl]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61846

--- Comment #2 from Zbigniew Jędrzejewski-Szmek <zbyszek at in dot waw.pl> ---
Created attachment 33151
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33151&action=edit
processed source