Linux 5.18 has no new syscalls. Update the version number in
syscall-names.list to reflect that it is still current for 5.18.
Tested with build-many-glibcs.py.
(cherry picked from commit
3d9926663cba19f40d26d8a8ab3b2a7cc09ffb13)
# This file can list all potential system calls. The names are only
# used if the installed kernel headers also provide them.
-# The list of system calls is current as of Linux 5.17.
-kernel 5.17
+# The list of system calls is current as of Linux 5.18.
+kernel 5.18
FAST_atomic_update
FAST_cmpxchg