Some shells (ksh in this case) don't say 'command not found'.

PR: 540

config

@@ -458,7 +458,7 @@ if [ "${SYSTEM}-${MACHINE}" = "Linux-alpha" ]; then
 fi
 
 if [ "${SYSTEM}" = "AIX" ]; then	# favor vendor cc over gcc
-    (cc) 2>&1 | grep -iv "command not found" > /dev/null && CC=cc
+    (cc) 2>&1 | grep -iv "not found" > /dev/null && CC=cc
 fi
 
 CCVER=${CCVER:-0}