Use GRegex for channel list search

This adds support for Windows

src/fe-gtk/fe-gtk.h

@@ -30,7 +30,6 @@
 
 #ifndef WIN32
 #include <sys/types.h>
-#include <regex.h>
 #endif
 
 #if defined(ENABLE_NLS) && !defined(_)
@@ -102,10 +101,8 @@ struct server_gui
 	gboolean chanlist_match_wants_channel;	/* match in channel name */
 	gboolean chanlist_match_wants_topic;	/* match in topic */
 
-#ifndef WIN32
-	regex_t chanlist_match_regex;	/* compiled regular expression here */
+	GRegex *chanlist_match_regex;	/* compiled regular expression here */
 	unsigned int have_regex;
-#endif
 
 	guint chanlist_users_found_count;	/* users total for all channels */
 	guint chanlist_users_shown_count;	/* users total for displayed channels */