Small fixes.

completion.c

@@ -60,7 +60,7 @@ list_files(zathura_t* zathura, const char* current_path, const char* current_fil
       goto error_free;
     }
 
-    int e_length = strlen(e_name);
+    size_t e_length = strlen(e_name);
 
     if (show_hidden == false && e_name[0] == '.') {
       g_free(e_name);
@@ -112,7 +112,7 @@ error_free:
   return NULL;
 }
 
-girara_completion_t*
+static girara_completion_t*
 list_files_for_cc(zathura_t* zathura, const char* input, bool check_file_ext)
 {
   girara_completion_t* completion  = girara_completion_init();