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/libminc/arch/i386/Makefile.libc.inc

@@ -6,11 +6,10 @@ SRCS+=  memchr.S memcmp.S memcpy.S memmove.S memset.S \
 .for i in infinityl.c
 .PATH.c: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/gen
 SRCS+= ${i}
-CPPFLAGS.${i}+= -I${LIBCSRCDIR}/include
 .endfor
 # Import from string
 .for i in bcmp.S
 .PATH.S: ${LIBCSRCDIR}/arch/${MACHINE_ARCH}/string
 SRCS+= ${i}
-CPPFLAGS.${i}+= -D_LIBC -I${LIBCSRCDIR}/include
+CPPFLAGS.${i}+= -D_LIBC
 .endfor