Fix some compiler warnings

`-Weverything' seems to have found a few problems.

Also enabled clang sanitizers by default.

src/kike.c

@@ -222,11 +222,11 @@ struct client
 	struct str read_buffer;             ///< Unprocessed input
 	struct str write_buffer;            ///< Output yet to be sent out
 
-	unsigned initialized    : 1;        ///< Has any data been received yet?
-	unsigned registered     : 1;        ///< The user has registered
+	bool initialized;                   ///< Has any data been received yet?
+	bool registered;                    ///< The user has registered
 
-	unsigned ssl_rx_want_tx : 1;        ///< SSL_read() wants to write
-	unsigned ssl_tx_want_rx : 1;        ///< SSL_write() wants to read
+	bool ssl_rx_want_tx;                ///< SSL_read() wants to write
+	bool ssl_tx_want_rx;                ///< SSL_write() wants to read
 	SSL *ssl;                           ///< SSL connection
 
 	char *nickname;                     ///< IRC nickname (main identifier)