NSH ls command: if node is a symobolic link, use readlink() to get and the display the target of the symblic link.

In apps/examples/mtdpart/mtdpart_main.c where CONFIG_EXAMPLES_MTDPART_NPARTITIONS defining is checked should be #ifndef instead of #ifdef.  Noted by Oleg Evseev

apps/examples/module and sotest:  Update for names changes resulting when module library was split out from kernel module code.

examples/module and examples/sotest can only be used in the FLAT build mode because they make illegal OS calls to ramdisk_register(), register_device(), and unregister_device().

synchronized compiler.h

Remvoe std_readline().  This called up_getc() and up_putc() directly, violating the POSIX OS interface.

examples/ostest: Add some delays to the pthread cancellation test.  With deferred cancellation enabled, things happen more asynchronously

examples/ostest:  Extend the pthread cancellation test to exercise pthread_cleanup_push() (and pthread_cleanup_pop() indirectly via pthread_cancel() and pthread_exit()