Because call rcu implementation is included within RCU flavors, calling
the RCU API goes through the API for non-LGPL code (this is a special
case for the RCU flavor implementation c file). Since this is clearly
LGPL code, we can use the inline versions.
It appears that just casting to "unsigned long" already has the semantic
we are looking for (checked by reading C99 standard and
experimentation): it sign-extends smaller signed integers, and does not
sign-extend unsigned integers.
Fix: preserve example files' timestamps when copying
This fixes an issue where examples were always being rebuilt
when performing an out of tree build since the examples were
being copied to the build directory with a timestamp more
recent than the already-built example objects.
