fix compiling in a messy way

A cleaner but more ugly solution would be to include text_object.h in
every header containing struct text_object definitions. But this
apparently triggers a big mess, since text_object.h itself includes
custom headers. Forward defining struct text_object is obviously the
mostly simple solution until there is a bigger header include review
cleaning it all up.

src/conky.h

@@ -63,6 +63,9 @@ char *strndup(const char *s, size_t n);
  * in every code file optionally using the feature
  */
 
+/* forward define to make gcc happy */
+struct text_object;
+
 #ifdef AUDACIOUS
 #include "audacious.h"
 #endif

src/eve.h

@@ -24,8 +24,6 @@
 #ifndef _EVE_H
 #define _EVE_H
 
-struct text_object;
-
 void scan_eve(struct text_object *, const char *);
 void print_eve(struct text_object *, char *, int);