[PATCH] um: Fix tgkill compile error on old host OSes

From: Yongting Lin tgkill is a quite old syscall since kernel 2.5.75, but unfortunately glibc doesn't support it before 2.30. Thus some systems fail to compile the latest UserMode Linux. Here is the compile error I encountered when I tried to compile UML in my system shipped with glibc-2.28.

Re: [PATCH] um: fix execve stub execution on old host OSs

Hi Glenn, Sun, 12 Jan 2025 14:07:36 -0600 Glenn Washburn wrote: >On Fri, 10 Jan 2025 17:13:05 +0100 >Benjamin Berg wrote: > >> From: Benjamin Berg >> >> The stub execution uses the somewhat new close_range and execveat >> syscalls. Of these two, the execveat call is essential, but the >> close