libc/minimal/assert: conditionalize static_assert macro

static_assert was not added to C until C11.  Zephyr builds default to
C99.  To preserve compatibility with newlib avoid defining the
macro at standard levels where it did not exist.

Relates to #17738 and #11754.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
1 file changed