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

lib/libfetch/http.c

@@ -68,8 +68,10 @@
 #define _GNU_SOURCE
 #endif
 
+#ifndef __minix
 /* Needed for gmtime_r on Interix */
 #define _REENTRANT
+#endif
 
 #if HAVE_CONFIG_H
 #include "config.h"