diff -urN a/configure b/configure
--- a/configure	2018-09-28 01:38:31.000000000 +0900
+++ b/configure	2019-05-22 15:17:05.722101952 +0900
@@ -3,52 +3,7 @@
 # This configure script written by Brian Callahan <bcallah@openbsd.org>
 # and released into the Public Domain.
 
-cccheck() {
-  if [ ! -z "$CC" ] ; then
-cat << EOF > conftest.c
-int main(void){return 0;}
-EOF
-    $CC -o conftest conftest.c > /dev/null 2>&1
-    if [ $? -eq 0 ] ; then
-      ./conftest
-      if [ $? -eq 0 ] ; then
-	rm -f conftest conftest.c
-	cc="$CC"
-	return 0
-      else
-	echo "could not build working executables"
-	echo "Please ensure your C compiler is a native compiler"
-	exit 1
-      fi
-    else
-      rm -f conftest conftest.c
-    fi
-  fi
-
-  for compiler in cc clang pcc xlc gcc ; do
-cat << EOF > conftest.c
-int main(void){return 0;}
-EOF
-
-    $compiler -o conftest conftest.c > /dev/null 2>&1
-
-    if [ $? -eq 0 ] ; then
-      ./conftest
-      if [ $? -eq 0 ] ; then
-	rm -f conftest conftest.c
-	cc="$compiler"
-	return 0
-      else
-	echo "could not build working executables"
-	echo "Please ensure your C compiler is a native compiler"
-	exit 1
-      fi
-    else
-      rm -f conftest conftest.c
-    fi
-  done
-  return 1
-}
+cc="$CC"
 
 fgetlncheck() {
   cat << EOF > conftest.c
@@ -162,18 +117,19 @@
   fi
 }
 
-wflagcheck() {
+futimenscheck() {
   cat << EOF > conftest.c
-int main(void){return 0;}
+#include <sys/stat.h>
+#include <stddef.h>
+int main(void){futimens(0, NULL);return 0;}
 EOF
-  $cc -w -o conftest conftest.c > /dev/null 2> conftest.err
-  grep ':' conftest.err > /dev/null 2>&1
+  $cc $tflags -o conftest conftest.c > /dev/null 2>&1
   if [ $? -eq 0 ] ; then
-    rm -f conftest conftest.err conftest.c
-    return 1
-  else
-    rm -f conftest conftest.err conftest.c
+    rm -f conftest conftest.c
     return 0
+  else
+    rm -f conftest conftest.c
+    return 1
   fi
 }
 
@@ -241,53 +197,9 @@
   ldflags="${ldflags}-static"
 fi
 
-printf "checking for C compiler... "
-cccheck
-if [ $? -ne 0 ] ; then
-  echo "not found"
-  echo "Please install a C compiler and re-run configure."
-  exit 1
-else
-  echo "$cc"
-fi
-
-printf "checking for -w compiler flag... "
-wflagcheck
-if [ $? -ne 0 ] ; then
-  echo "no"
-else
-  cflags="$cflags -w"
-  echo "yes"
-fi
-
-printf "checking for OS... "
-libs='-lncurses'
-os=`uname -s`
-echo "$os"
-
-case "x$os" in
-  "xLinux"|"xCYGWIN"*)
-    cflags="$cflags -D_GNU_SOURCE -D__dead=\"__attribute__((__noreturn__))\" -Dst_mtimespec=st_mtim"
-    ;;
-  "xDarwin")
-    cflags="$cflags -DMSG_NOSIGNAL=SO_NOSIGPIPE -DLOGIN_NAME_MAX=MAXLOGNAME"
-    libs="$libs -lutil"
-    ;;
-  "xFreeBSD")
-    cflags="$cflags -D__dead=__dead2 -DLOGIN_NAME_MAX=MAXLOGNAME"
-    libs="$libs -lutil"
-    ;;
-  "xOpenBSD")
-    libs="$libs -lutil"
-    ;;
-  "xNetBSD")
-    libs="$libs -lutil"
-    ;;
-  "xDragonFly")
-    cflags="$cflags -D__dead=__dead2 -DLOGIN_NAME_MAX=MAXLOGNAME"
-    libs="$libs -lutil"
-    ;;
-esac
+# OpenWrt
+libs='-lncurses -lpcre'
+cflags="$cflags -D_GNU_SOURCE -D__dead=\"__attribute__((__noreturn__))\" -Dst_mtimespec=st_mtim"
 
 cat << EOF > config.h
 /* This file generated automatically by configure.  */
@@ -370,6 +282,15 @@
   echo "no"
 fi
 
+printf "checking for futimens... "
+futimenscheck
+if [ $? -eq 0 ] ; then
+    echo "#define HAVE_FUTIMENS" >> config.h
+    echo "yes"
+else
+    echo "no"
+fi
+
 printf "creating Makefile... "
 cat << EOF > Makefile
 # This Makefile automatically generated by configure.