The hardware reset state of the the MPU precludes any bus
   masters other then DMA access to memory. Unfortunately
   USB and SDHC have there own DMA and will not have access to
   memory in the default reset state.

   This change disabled the MPU if present on system startup.

MTD FLASH drivers:  The byte write method of several drivers had a cloned error:  It was not locking the bus while performing byte write operations.

libfflush remove extra semicolon

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

Comment out most of 430060e9.  Clean-up some dependencies in top-level Makefile

This reverts commit 430060e9.

That commit has some unexpected side-effects

tools/:  Add initialconfig.c so that perhaps in the future we will be able to use this to generate a new configuration from scratch (rather than having to derive new configurations from existing configurations)

nucleo-f4x1re User LEDS: Issue #51 reports compilation problems with stm32_userled.c.  Reported by Gappi92.

Tiva SSI:  Resolves issue 52 'Copy-Paste error in tiva_ssibus_initialize()' submitted by Aleksandr Kazantsev.

Makefiles.*: It should be possible to run 'make menuconfig' with no .config and no Make.defs file.  This change removes the dependency on Make.defs, but does not solve the problem of the missing .config file.  Without a .config file, it is not currently possible for the Makefile.* to correctly setup up the symbolic links to directories.

pthread robust mutexes:  Fix memmory trashing problem:  the main task may also use mutexes; need to check thread type before accessing pthread-specific mutex data structures.  Problem noted by Jussi Kivilinna.

vfs: fdopen: add missing file stream flags clearing.  Clear file stream structure regardless of config options. Structure clearing is needed as previous use of stream list entry might leave fs_flags set.