There is a typo in sem_unlink_alt.diff, not in the patch itself but in the neighbouring lines. In Modules/_multiprocessing/semaphore.c, it should be, I think, after one does 's/define sem_unlink(name)/define SEM_UNLINK(name)/':

@@ -194,8 +194,8 @@
 #  define SEM_FAILED ((sem_t *)-1)
 #endif
 
-#ifndef HAVE_SEM_UNLINK
-#  define sem_unlink(name) 0
+#if !defined(HAVE_SEM_UNLINK) || defined(__ANDROID__)
+#  define SEM_UNLINK(name) 0
 #endif
 
 #ifndef HAVE_SEM_TIMEDWAIT


But applying this new patch, gives exactly the same results. Maybe it is not just sem_unlink() that is not implemented. I will run a gdb session to find out.