[PATCH v3 0/4] make POSIX timers optional with some Kconfig help

[Nicolas Pitre]

Many embedded systems don't need the full POSIX timer support.
Configuring them out provides a nice kernel image size reduction.

When POSIX timers are configured out, the PTP clock subsystem should be
left out as well. However a bunch of ethernet drivers currently *select*
the later in their Kconfig entries. Therefore some more work was needed
to break that hard dependency from those drivers without preventing their
usage altogether.

Therefore this series also includes kconfig changes to implement a new
keyword to express some reverse dependencies like "select" does, named
"imply", and still allowing for the target config symbol to be disabled
if the user or a direct dependency says so.

At this point I'd like to gather ACKs especially from people in the "To"
field. Ideally this would need to go upstream as a single series to avoid
cross subsystem dependency issues.  So far it was suggested that this should go
via the kbuild tree.

Changes from v2:

- Dropped the patch adding the "suggest" keyword as nothing uses it.
  Requested by Paul Bolle.
- Various documentation and commit log clarifications, prompted also
  by Paul Bolle.
- Collected more ACKs.

Changes from v1:

- added "suggest" to kconfig for completeness
- various typo fixes
- small "imply" effect visibility fix

The bulk of the diffstat comes from the kconfig lex parser regeneration.

Diffstat:

 Documentation/kbuild/kconfig-language.txt       |   29 +
 drivers/Makefile                                |    2 +-
 drivers/net/ethernet/adi/Kconfig                |    2 +-
 drivers/net/ethernet/amd/Kconfig                |    2 +-
 drivers/net/ethernet/amd/xgbe/xgbe-main.c       |    6 +-
 drivers/net/ethernet/broadcom/Kconfig           |    4 +-
 drivers/net/ethernet/cavium/Kconfig             |    2 +-
 drivers/net/ethernet/freescale/Kconfig          |    2 +-
 drivers/net/ethernet/intel/Kconfig              |   10 +-
 drivers/net/ethernet/mellanox/mlx4/Kconfig      |    2 +-
 drivers/net/ethernet/mellanox/mlx5/core/Kconfig |    2 +-
 drivers/net/ethernet/renesas/Kconfig            |    2 +-
 drivers/net/ethernet/samsung/Kconfig            |    2 +-
 drivers/net/ethernet/sfc/Kconfig                |    2 +-
 drivers/net/ethernet/stmicro/stmmac/Kconfig     |    2 +-
 drivers/net/ethernet/ti/Kconfig                 |    2 +-
 drivers/net/ethernet/tile/Kconfig               |    2 +-
 drivers/ptp/Kconfig                             |   10 +-
 include/linux/posix-timers.h                    |   28 +-
 include/linux/ptp_clock_kernel.h                |   65 +-
 include/linux/sched.h                           |   10 +
 init/Kconfig                                    |   17 +
 kernel/signal.c                                 |    4 +
 kernel/time/Makefile                            |   10 +-
 kernel/time/posix-stubs.c                       |  118 ++
 scripts/kconfig/expr.h                          |    2 +
 scripts/kconfig/menu.c                          |   55 +-
 scripts/kconfig/symbol.c                        |   24 +-
 scripts/kconfig/zconf.gperf                     |    1 +
 scripts/kconfig/zconf.hash.c_shipped            |   30 +-
 scripts/kconfig/zconf.tab.c_shipped             | 1581 ++++++++---------
 scripts/kconfig/zconf.y                         |   16 +-
 32 files changed, 1114 insertions(+), 932 deletions(-)