Allow user-defined settings without editing header files by using
POLARSSL_CONFIG_OPTIONS in config.h
(cherry picked from commit 6fa5488779c5b50bf13f9250e19d25c6c6cf9bcf)
Conflicts:
include/polarssl/config.h
- As a consequence all error code that were positive were changed. A lot of MALLOC_FAILED and FILE_IO_ERROR error codes added for different modules.
- Programs and tests were adapted accordingly