diff --git a/configure.in b/configure.in
index c5a31bf33..2cef580fd 100644
--- a/configure.in
+++ b/configure.in
@@ -14,10 +14,6 @@ AC_CANONICAL_HOST
 dnl Checks for programs.
 AC_PROG_CC
 # AC_PROG_CC_C99 is only available in autoconf version 2.60 and later.
-# If you must use an older version then comment out the following two
-# lines, but be warned that there could be issues with finding the
-# nan(), etc. functions. It is really best to upgrade to a supported
-# version of autoconf.
 AC_PREREQ([2.60])
 AC_PROG_CC_C99
 AC_PROG_CXX