Port changes to original duktape source

[mitar]

Currently, this code is modified from the release tarball. We should also wrap code changes in a new config flag or something.

Some notes:

duktape-dist

• SGX include dirs, /NODEFAULTLIB - Compile for SGX platform.
• DUK_OPT_NO_FILE_IO - File I/O is not available in enclave.
• DUK_OPT_CPP_EXCEPTIONS - The SGX SDK doesn't support setjmp.
• DUK_OPT_NO_JX - The SGX SDK doesn't support sscanf, which JX needs.
• /TP - Compile as C++ because we need C++ exceptions.

Code changes (duktape-dist)

• DUK_SNPRINTF in duk_bi_date.c - The SGX SDK doesn't support sprintf (without the "n"). Provide DUK_BI_DATE_ISO8601_BUFSIZE.
• duk_bi_date_get_*_sgx - Stubbed out routines for getting the time and locale information from the OS. Consider using SGX's Trusted Time system to implement this for real.
• Don't include <windows.h> - We're not running on Windows.
• Don't include <setjmp.h> - The SGX SDK doesn't have this file.
• Use unprefixed snprintf and vsnprintf - That's what the SGX SDK provides.
• Remove duk_file and DUK_STD* - The SGX SDK doesn't provide the underlying FILE and std*.