+/** Create a new G-line and add it to global lists.
+ * \a userhost may be in one of four forms:
+ * \li A channel name, to add a BadChan.
+ * \li A string starting with $R and followed by a mask to match against their realname.
+ * \li A user\@IP mask (user\@ part optional) to create an IP-based ban.
+ * \li A user\@host mask (user\@ part optional) to create a hostname ban.
+ *
+ * @param[in] cptr Client that sent us the G-line.
+ * @param[in] sptr Client that originated the G-line.
+ * @param[in] userhost Text mask for the G-line.
+ * @param[in] reason Reason for G-line.
+ * @param[in] expire Duration of G-line in seconds.
+ * @param[in] lastmod Last modification time of G-line.
+ * @param[in] flags Bitwise combination of GLINE_* flags.
+ * @return Zero or CPTR_KILLED, depending on whether \a sptr is suicidal.
+ */