Add workarounds for current compilers

With current compilers, we're getting "this function cannot be inlined"
errors on vsnprintf and strlcpy because the always_inline attribute is
set.

Before marking this a "fix" instead of a "workaround", we should figure
out why the functions can't be inlined.

Signed-off-by: Amit Pundir <amit.pundir@linaro.org>