diff --git a/configure.ac b/configure.ac
index e915b6ab..34916771 100644
--- a/configure.ac
+++ b/configure.ac
@@ -29,7 +29,6 @@ AM_MAINTAINER_MODE
 
 dnl Checks for programs.
 AC_PROG_CC
-AC_ISC_POSIX
 AC_PROG_LN_S
 AC_PROG_YACC
 AM_PROG_LIBTOOL