We don't actually want Coverity to complain when a BUG() check can
never fail, since such checks can prevent us from introducing bugs
later on.
Closes ticket 23054. Closes CID 1415720, 1415724.
In the Linux kernel, the BUG() macro causes an instant panic. Our
BUG() macro is different, however: it generates a nonfatal assertion
failure, and is usable as an expression.
Additionally, this patch tells util_bug.h to make all assertion
failures into fatal conditions when we're building with a static
analysis tool, so that the analysis tool can look for instances
where they're reachable.
Fixes bug 23030.
Unlike tor_assert(), these macros don't abort the process. They're
good for checking conditions we want to warn about, but which don't
warrant a full crash.
This commit also changes the default implementation for
tor_fragile_assert() to tor_assert_nonfatal_unreached_once().
Closes ticket 18613.
