gchar *dypname; is on line 437 between #ifdef HAVE_LIBSTARTUP_NOTIFICATION and #else, but the variable is used on lines 495-497 between #else and #endif, resulting in:
launcher-exec.c: In function 'launcher_exec_on_screen':
launcher-exec.c:495: error: 'dpyname' undeclared (first use in this function)
launcher-exec.c:495: error: (Each undeclared identifier is reported only once
launcher-exec.c:495: error: for each function it appears in.)
when compiled with --disable-startup-notification