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

kernel/extract-errno.sh

@@ -3,7 +3,7 @@
 set -e
 
 # grep message type and errno constants and make them into a .h file
-cat ../include/sys/errno.h | \
+cat ../sys/sys/errno.h | \
 tr -s ' \t' ' ' | \
 sed 's/^# /#/' | \
 egrep '^#define [A-Z_][A-Z0-9_]* \( ?_SIGN ?[0-9]+ ?\)' | \