Re-add _ISbit macro required to build libstdc++ from gcc toolchain.
Re-add _ISbit macro required to build libstdc++ from gcc toolchain.

Signed-off-by: Carmelo Amoroso <532378793705a04edd56deb76ad8c0442834d55d@st.com>


joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc