[NEWLIB] Updated with _calloc_r() fix.
[BTDK] Updated the build and configure process. Added a libc.install step to copy libraries not copied by newlib install target.
[NEWLIB] Updated newlib with support for various open modes.
[BTDK] Updated the install-libc.sh script to copy the optimised libm etc libs.
[NEWLIB] Updated newlib with support for seeking.