Add logic to VFS rename:  If target of rename exists and is a directory, then the source file should be moved 'under' the target directory.  POSIX also requires that if the target is a file, then that old file must be deleted.

Minor typos

Approved-by: Gregory Nutt

Apparently setvbuf() size can be nonzero with _IONBF.  That makes no sense, but is necessary if setbuf() is to work as it is defined at OpenGroup.org.

Merged in david_s5/nuttx-6/david_s5/typo-up_exitc-edited-online-with-bitbuck-1486672675169 (pull request #207)

Typo up_exit.c edited online with Bitbucket

Approved-by: Gregory Nutt

STM32 & STM32F7 Fixes the bkp reference counter issue

Approved-by: Gregory Nutt

  Allow for complete MCG_C2 definition from the boart.h file
  Moved #ifdef out of code by setting default values for
  Allow for individule bit setting in MCG_C2 for
    BOARD_EXTCLOCK_MCG_C2
    BOARD_MCG_C2_FCFTRIM
    BOARD_MCG_C2_LOCRE0
  Added range and sanity checking

  Added BOARD_MCG_C2_FCFTRIM and BOARD_MCG_C2_LOCRE0 to
  configure the MCG_C2 register
  cleanup of some comments

  Original BOARD_FR_DIV was never used - that is a good thing because
  the value ws definec shifted and the code also shifited it.

  We define the bits as a common set of names. This means that
  an index may be added to a name i.e. LOCK is LOCK0 as that is
  the superset name.

  This includes arch/arm/include/kinetis/kinetis_mcg.h
  to bring in the MCG versioning and defines the KINETIS_K66
  family for the added SoCs:

   --------------- ------- --- ------- ------- ------ ------ ------ -----
   PART NUMBER     CPU     PIN PACKAGE  TOTAL  PROGRAM EEPROM SRAM  GPIO
                   FREQ    CNT          FLASH  FLASH
   --------------- ------- --- ------- ------- ------ ------ ------ -----
   MK66FN2M0VMD18  180 MHz 144 MAPBGA   2   MB    —    — KB  260 KB 100
   MK66FX1M0VMD18  180 MHz 144 MAPBGA  1.25 MB  1 MB   4 KB  256 KB 100
   MK66FN2M0VLQ18  180 MHz 144 LQFP     2   MB    —    — KB  260 KB 100
   MK66FX1M0VLQ18  180 MHz 144 LQFP    1.25 MB  1 MB   4 KB  256 KB 100

   The motvations is to version the IP blocks of the Kinetis
   K series family of parts.

   This added versioning and configuration features for the
   Kinetis MCG IP block.

   It is envisioned that in the long term as a chip is added.
   The author of the new chip definitions will either find
   the exact configuration in an existing  chip define and
   add the new chip to it Or add the MCG feature configuration
   #defines to the chip ifdef list in
   arch/arm/include/kinetis/kinetis_mcg.h  In either case the
   author should mark it as "Verified to Document Number:"
   taken from the reference manual.

   The version KINETIS_MCG_VERSION_UKN has been applied to
   most all the SoCs in the kinetis arch prior to this commit.

   The exceptions are the CONFIG_ARCH_CHIP_MK60FN1M0VLQ12,
   All K64 and K66 which not have Verified MCG configurations.