cppcheck: fix various warnings/errors

cppcheck: fix various warnings/errors

[ircd/match.c:316]: (error) Shifting a negative value is undefined behaviour
[librb/src/patricia.c:55]: (error) Shifting a negative value is undefined behaviour
[modules/m_alias.c:64]: (portability) '(void*)message' is of type 'void *'. When using void pointers in calculations, the behaviour is undefined.
[modules/m_time.c:111]: (warning) %u in format string (no. 9) requires 'unsigned int' but the argument type is 'signed int'.
[modules/m_time.c:111]: (warning) %u in format string (no. 10) requires 'unsigned int' but the argument type is 'signed int'.
[librb/src/dictionary.c:819]: (warning) %d in format string (no. 3) requires 'int' but the argument type is 'unsigned int'.
[librb/src/radixtree.c:1080]: (warning) %d in format string (no. 3) requires 'int' but the argument type is 'unsigned int'.
[ircd/s_user.c:351] -> [ircd/s_user.c:357]: (warning) Either the condition '0!=source_p' is redundant or there is possible null pointer dereference: source_p.
[extensions/ip_cloaking_3.0.c:109]: (warning, inconclusive) The buffer 'buf' may not be null-terminated after the call to strncpy().
[ircd/chmode.c:256]: (style) Clarify calculation precedence for '&' and '?'.
[modules/m_help.c:100]: (style) Clarify calculation precedence for '&' and '?'.
[modules/m_knock.c:169]: (style) Clarify calculation precedence for '&' and '?'.
[modules/m_stats.c:628]: (style) Clarify calculation precedence for '&' and '?'.
[modules/m_stats.c:727]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:601]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:704]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:739]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:763]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:768]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:774]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:781]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:786]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:791]: (style) Clarify calculation precedence for '&' and '?'.
[librb/src/radixtree.c:804]: (style) Clarify calculation precedence for '&' and '?'.
[ircd/wsproc.c:372]: (style) Unused variable: len
[modules/core/m_modules.c:382]: (style) Unused variable: i
[modules/m_stats.c:741]: (style) Unused variable: amsg
[ircd/authproc.c:390]: (style) Unused variable: iter
[ircd/authproc.c:391]: (style) Unused variable: client_p