Get output and error streams from the command spawned by external_call()

Signed-off-by: Pierre Mazière <pierre.maziere@gmx.com>

src/common.h

@@ -106,6 +106,6 @@ void get_file_paths_recursive(const char *directory, GSList **contents);
 
 char* get_random_string(int length);
 
-void call_external(const char *const exe, const char *const param);
+gboolean call_external(gchar **argv, gchar ***const output_ptr, gchar ***const error_ptr);
 
 #endif