ARMv7-A: Modify up_fullcontextrestore() for CONFIG_BUILD_KERNEL.  It changed CPSR while in kernel.  That will crash is the new CPSR is user mode while executing in kernel space.  Fixed by adding a SYS_context_restore system call.  There is an alternative, simpler modification to up_fullcontextrestore() that could have been done:  It might have been possible to use the SPSR instead of the CPRSR and then do an exception return from up_fullcontextrestore().  That would be more efficient, but I never tried it.

Misc fixes to repair some of the breakage to the SAMA5D4-EK elf configuration caused by changes for the knsh configuration

When a privileged thread exits, we have to use the kernel alloctor to free memory; when an unprivileged thread exits, we don't have to do anything... heap memory will be cleaned up when the address environment is torn down

SAMA5D4-EK: These configurations now use the fixed DRAM mapping for manipulating the page memory pool.

Add logic that will permit us to build user libraries with different CFLAGS than kernel code.  This is needed because we need the -fno-common option when building ELF code to prevent SHN_COMMON relocations

SAM3X/Arduino Due: Fix typo in sam3x_periphclks.h; add SCLK definitions to board.h header file.  From Fabien Comte

SAM3X/Arduino Due: Fix typo in sam3x_periphclks.h; add SCLK definitions to board.h header file.  From Fabien Comte

Remove the 16z board support from the main source tree.  It is still avaialable in the misc/Obsoleted directory

Obsolete support for the 8051 family.  Trying to maintain compatibility with this family is too much effort and there has never really been a successful NuttX impplementation on these parts

SAMA5D4-EK:  Add a configuration for testing the kernel build configuration (still a work in progress)

Separate flat, protected, and kernel mode library selected into separate files.  The conditional logic as exceed my able to comprehend and maintain the selections.