Linux plugin: wait4.c: no such file or directory

I’m trying to adapt an existing plugin to work on Linux. The plugin is UnrealInk . I’ve made a huge amount of progress porting it. But I’m still stuck. Now, it’s recognized by Unreal, but it crashes it. Some files were missing. Currently, I’m adding them by hand, temporarily. But when I do, I get this error message:

[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
0x00007f761fe90dff in __GI___wait4 (pid=555254, stat_loc=0x7ffc75434034, options=0, usage=0x0) at ../sysdeps/unix/sysv/linux/wait4.c:27
27      ../sysdeps/unix/sysv/linux/wait4.c: No such file or directory.

I don’t know what that’s about. The file specified, sysdeps/unix/sysv/linux/wait4.c, does not exist on my file system. I’ve tried adding the following to the xxx.Build.cs:

PublicDelayLoadDLLs.Add("libc");

Because wait is part of libc. It builds but still says that the file cannot be found.

I don’t know what to do next.

Does anyone have an idea?