diff --git a/configure.ac b/configure.ac
index 883ff11b..651806de 100644
--- a/configure.ac
+++ b/configure.ac
@@ -328,6 +328,7 @@ AM_CONDITIONAL(NO_GETOPT, [test "x$found_getopt" = xno])
 AC_CHECK_FUNCS(
 	[ \
 		bzero \
+		dirfd \
 		setproctitle \
 		sysconf \
 	]
@@ -401,15 +402,6 @@ else
 	AC_MSG_RESULT(no)
 fi
 
-# Look for /proc/$$/fd.
-AC_MSG_CHECKING(for /proc/\$\$/fd)
-if test -d /proc/$$/fd; then
-	AC_DEFINE(HAVE_DIRFD)
-	AC_MSG_RESULT(yes)
-else
-	AC_MSG_RESULT(no)
-fi
-
 # Figure out the platform for osdep-*.c and forkpty-*.c.
 AC_MSG_CHECKING(platform)
 case "$host_os" in