/usr/lib/x86_64-linux-gnu/pkgconfig/pthread-stubs.pc is in libpthread-stubs0-dev 0.3-4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | prefix=/usr
exec_prefix=${prefix}
libdir=${prefix}/lib/x86_64-linux-gnu
Name: pthread stubs
Description: Stubs missing from libc for standard pthread functions
Version: 0.3
Libs:
|