I was trying to compile geany (https://github.com/b4n/geany/tree/wip/gtk3-support), but I get errors like this:

~/geany-wip-gtk3-support/tagmanager/src'
  CC       tm_file_entry.o
tm_file_entry.c:35:66: error: expected ‘;’, ‘,’ or ‘)’ before ‘user_data’
 void tm_file_entry_print(TMFileEntry *entry, gpointer __unused__ user_data


It continues compilation when I remove "__unused__", but the error happens again and again (probably hundreds of times). Are there special compiler parameters necessary? Why does it not just work with "make"?
I was also wondering if I caught the correct source code, since it seems to be missing commits for over a year.

I used: Ubuntu 14.04, GNU Make 3.81