Libraries updates and cleanup

* Updating common/lib
 * Updating lib/csu
 * Updating lib/libc
 * Updating libexec/ld.elf_so
 * Corrected test on __minix in featuretest to actually follow the
   meaning of the comment.
 * Cleaned up _REENTRANT-related defintions.
 * Disabled -D_REENTRANT for libfetch
 * Removing some unneeded __NBSD_LIBC defines and tests

Change-Id: Ic1394baef74d11b9f86b312f5ff4bbc3cbf72ce2

servers/ext2/write.c

@@ -37,7 +37,7 @@ int op;				/* special actions */
  * the double/triple indirect block.
  * It's the only function which should take care about rip->i_blocks counter.
  */
-  int index1, index2, index3; /* indexes in single..triple indirect blocks */
+  int index1 = 0, index2 = 0, index3 = 0; /* indexes in single..triple indirect blocks */
   long excess, block_pos;
   char new_ind = 0, new_dbl = 0, new_triple = 0;
   int single = 0, triple = 0;