Avoid using file names and file paths for compatibility with
out-of-tree builds.
Note make and ccache don't track blacklist dependencies,
add workarounds.
Document use of coverity, clang static analyzer, and clang dynamic
undefined behavior and address sanitizers in doc/HACKING.
Add clang dynamic sanitizer blacklist in
contrib/clang/sanitizer_blacklist.txt to exempt known undefined
behavior. Include detailed usage instructions in this blacklist file.
Patch by "teor".