Sync with Circle Step 37 and mbed TLS 2.14.1

• Synced with Circle Step 37.
• Synced with mbed TLS 2.14.1.

Sync with Circle Step 36

• Synced with Circle Step 36, no further changes

Sync with Circle Step 35.1

• Synced with Circle Step 35.1.
• Added support for <dirent.h> functions.
• Added support for time()-related functions.
• mbed TLS support implemented by Rene Stange.
• Added configure script and Makefile to replace build.bash. build.bash is
  deprecated and will be removed in a future release.

Sync with Circle Step 34

v4.0

Prepare v4.0 release

C++ Standard Library Support

• Synced with Circle Step 33.
• Implemented stdin/stdout/stderr based on Circle's CConsole class.
• A build of circle-stdlib with ARM gcc toolchains that include Newlib out-of-the-box now provides support for C and C++ standard libraries. This is due to the fact that the Newlib provided by the toolchain is replaced by circle-stdlib's Newlib build, and the toolchain's standard C++ library works with the replaced Newlib.

Fixed Build Problems

v2.2

Needs all Circle libraries because of stdio support.

Fixed Clone Problem with Circle Submodule

Cloning according to the instructions failed because the reference to the Circle submodule needs to point to the Circle fork that has the necessary changes for supporting the v2.0 features.

I/O System Calls Implemented

This release implements Newlib's open(), close(), read() and write() system calls bases on Circle's I/O functions. This enables stdio functionality.

Notes:

• The lseek() system call is not implemented, because Circle provides no seek functionality. This means that fseek() does not work as well.
• stdin, stdout and stderr are not implemented yet.

Newlib for Circle without any system calls being implemented

As a first step Newlib is built without any system calls being implemented. This means that all features that do not depend on system calls should work (e.g. math functions, setjmp/longjmp, bsearch, qsort), but everything that depends on system calls like open, read etc. does not work and returns errors (e.g. stdio functions).