This commit backs out most of commit b4747286b1. That change was added because sem_wait() would sometimes cause cancellation points inappropriated. But with these recent changes, nxsem_wait() is used instead and it is not a cancellation point.
In the OS, all calls to sem_wait() changed to nxsem_wait(). nxsem_wait() does not return errors via errno so each place where nxsem_wait() is now called must not examine the errno variable.
In all OS functions (not libraries), change sem_wait() to nxsem_wait(). This will prevent the OS from creating bogus cancellation points and from modifying the per-task errno variable.
sched/semaphore: Add the function nxsem_wait(). This is a new internal OS interface. It is functionally equivalent to sem_wait() except that (1) it is not a cancellation point, and (2) it does not set the per-thread errno value on return.
sched/semaphore: Add nxsem_post() which is identical to sem_post() except that it never modifies the errno variable. Changed all references to sem_post in the OS to nxsem_post().
sched/semaphore: Add nxsem_destroy() which is identical to sem_destroy() except that it never modifies the errno variable. Changed all references to sem_destroy() in the OS to nxsem_destroy().
libc/semaphore and sched/semaphore: Add nxsem_getprotocol() and nxsem_setprotocola which are identical to sem_getprotocol() and set_setprotocol() except that they never modifies the errno variable. Changed all references to sem_setprotocol in the OS to nxsem_setprotocol(). sem_getprotocol() was not used in the OS
Merged in merlin17/nuttx/mac802154-sock (pull request #479)
wireless/ieee802154: Adds support for receiving MAC events via IOCTL through socket interface. Other small fixes and cleanup
* ioctl: Cleans up MAC802154IOC values
* wireless/ieee802154: Cleans up MAC802154IOC_NOTIFY_REGISTER logic in character driver
* wireless/ieee802154/mac802154_netdev: Adds support for MAC event notification via IOCTL
* wireless/ieee802154/mac802154: Changes reset logic. No longer reset extended address.
* wireless/ieee802154: Cleans up MAC802154IOC logic
Moves MAC802154IOC from ieee802154_ioctl.h and renames ieee802154_ioctl.h to ieee802154_device.h since it only contains types relevant to the MAC char device now.
* wireless/ieee802154/mac802154_device: Cleans up IOCTL logic for recent changes.
* drivers/wireless/ieee802154/mrf24j40: Adds missing break in case statement
* wireless/ieee802154/mac802154_netdev: Starts adding support for passing MAC events via IOCTL
* wireless/ieee802154/mac802154: Fixes issue with receiver enable logic
* wireless/ieee802154/mac802154: Fixes issue where extended address is cleared and not rewritten after radio reset
* configs/clicker2-stm32/mrf24j40-mac: Enables RAMLOG and wireless driver logging
* wireless/ieee802154/mac802154: Fixes poll logic meant to automatically choose address mode based on short address range.
Approved-by: Gregory Nutt <gnutt@nuttx.org>
