[seccomp/libseccomp] 3796e2: doc: Add BUGS section to seccomp_rule_add.3

[Tom Hromatka]

Branch: refs/heads/release-2.5
Home: https://github.com/seccomp/libseccomp
Commit: 3796e2789ba829983551787bfc41ea0636af8541
https://github.com/seccomp/libseccomp/commit/3796e2789ba829983551787bfc41ea0636af8541
Author: Tom Hromatka <tom.hr...@oracle.com>
Date: 2021-08-23 (Mon, 23 Aug 2021)

Changed paths:
M doc/man/man3/seccomp_rule_add.3

Log Message:
-----------
doc: Add BUGS section to seccomp_rule_add.3

Add BUGS section to seccomp_rule_add.3 and add a warning about
adding a seccomp filter to syscalls that are always expected to
succeed.

PowerPC's glibc behaves differently from other architectures and
will not return a negative number for the getpid() syscall.

Fixes: https://github.com/seccomp/libseccomp/issues/313
Acked-by: Paul Moore <pa...@paul-moore.com>
Signed-off-by: Tom Hromatka <tom.hr...@oracle.com>

(imported from commit b9a8f3dbdfe84bfe7802bb9532253cc0a46b5b8a)