mklib: Ensure target directory exists for library

Instead of relying on the Makefile to always generate $(TOP)/$(LIB_DIR),
just have mklib handle creating the directory. This should fix any races
when using parallel make.

Signed-off-by: Dan Nicholson <dbn.lists@gmail.com>
(cherry picked from commit 23671e5358)

bin/mklib

@@ -971,5 +971,6 @@ esac
 #
 if [ ${INSTALLDIR} != "." ] ; then
     echo "mklib: Installing" ${FINAL_LIBS} "in" ${INSTALLDIR}
+    test -d ${INSTALLDIR} || mkdir -p ${INSTALLDIR}
     mv ${FINAL_LIBS} ${INSTALLDIR}/
 fi