examples/ostest:  pthread rwlock cleanup handlers must call pthread_consistent, not pthread_mutex_unlock() on cancellation if robust mutexes are enabled.

pthreads: Re-order some operations so that mutexes are placed in the inconsistent state BEFORE the clean-up callbacks are called.

Photon:  Add logic to automatically mount the procfs file system on startup.  Fix some LED-related configuration conflicts.

stm32 COMP:  Logic in stm32_comp.h must be configured on CONFIG_STM32_COMP or otherwise it causes an error via #error on every platform without COMP support.

net procfs: Some long lines were being generated that cause buffer-related problems and corrupted output

Add support for NuttX controlled LEDS and for board_initialize.  Separate initialize logic to stm32_bringup.c so that in initialization can occur either through board_initialize() or through board_app_initialize().  Same as with most other newer board configurations.

Fix photon/nsh/defconfig, was turning on non-existent LED support when the configuration was refreshed.

Buttons: Change return value of board_buttons() and the type of btn_buttonset_t to uint32_t so that more than 8 buttons can be supported.

6loWPAN: Fix breakage in IPv6 dispatch caused by fixes to HC1 dispatch; Move some standard definitions from internal header file to include/nuttx/net/sixlowpan.h.  Update a README.

pthread.h:  Remove duplicate, possible erroneous definitino of PTHREAD_MUTEX_INITIALIZER that crept in with some recent changes.

Restore TCP_HDRLEN to MSS calculation.  Also add to UDP MSS calculation where it never appearred.  Add some missing MSS and RDVWNDO definitinos for 6loWOPAN.

Adding an implementation for read/write locks into the pthread library.
These locks are writer priority, such that if any writers come in they
are given priority for writing.

Disable serial console on stm32f103-minimum usbnsh example project config. Devices enumerate after this change.

Approved-by: Gregory Nutt <gnutt@nuttx.org>

Disable serial console on stm32f103-minimum usbnsh example project config. Devices enumerate after this change.

6loWPAN: Back out part of the last commit.  That included two fixes for a problem.  One that didn't work and is unnecessary and one that is necessary.  The commit removes the former.

EFM32 I2C: Fix timeout calculation

Approved-by: Gregory Nutt <gnutt@nuttx.org>

New interface allows checking if RTC time has been set.  This allows to application to detect if RTC has valid time (after
reset) or should application attempt to get real time by other means (for example, by launching ntpclient or GPS).