mention that egrep and ar are also mandatory

CHANGES

@@ -28,7 +28,8 @@ Yang Tse (2 Jul 2008)
   will fallback to gettimeofday when the monotonic clock is unavailable at
   run-time.
 
-- The configure process will now halt when sed or grep are unavailable.
+- The configure process will now halt when sed, grep, egrep or ar programs
+  can not be found among the directories in PATH variable.
 
 Daniel Stenberg (1 Jul 2008)
 - Rolland Dudemaine provided fixes to get libcurl to build for the INTEGRITY