diff --git a/configure b/configure
index 61c2b288d..ffa73a54d 100755
--- a/configure
+++ b/configure
@@ -23032,9 +23032,7 @@ $as_echo "yes" >&6; }
 	have_dbus=yes
 fi
         save_CPPFLAGS="$CPPFLAGS"
-        save_CFLAGS="$CFLAGS"
         CPPFLAGS="$save_CPPFLAGS $DBUS_CFLAGS"
-        CFLAGS="$save_CFLAGS $DBUS_CFLAGS"
         ac_fn_c_check_header_mongrel "$LINENO" "dbus/dbus.h" "ac_cv_header_dbus_dbus_h" "$ac_includes_default"
 if test "x$ac_cv_header_dbus_dbus_h" = xyes; then :
   have_dbus_dbus_h_hdr=yes
@@ -23044,7 +23042,6 @@ fi
 
 
         CPPFLAGS="$save_CPPFLAGS"
-        CFLAGS="$save_CFLAGS"
         if test x$have_dbus_dbus_h_hdr = xyes; then
 
 $as_echo "#define HAVE_DBUS_DBUS_H 1" >>confdefs.h
@@ -23208,9 +23205,7 @@ $as_echo "yes" >&6; }
 	have_ibus=yes
 fi
         save_CPPFLAGS="$CPPFLAGS"
-        save_CFLAGS="$CFLAGS"
         CPPFLAGS="$save_CPPFLAGS $IBUS_CFLAGS"
-        CFLAGS="$save_CFLAGS $IBUS_CFLAGS"
         ac_fn_c_check_header_mongrel "$LINENO" "ibus-1.0/ibus.h" "ac_cv_header_ibus_1_0_ibus_h" "$ac_includes_default"
 if test "x$ac_cv_header_ibus_1_0_ibus_h" = xyes; then :
   have_ibus_ibus_h_hdr=yes
@@ -23220,7 +23215,6 @@ fi
 
 
         CPPFLAGS="$save_CPPFLAGS"
-        CFLAGS="$save_CFLAGS"
         if test x$have_ibus_ibus_h_hdr = xyes; then
             if test x$enable_ime != xyes; then
                 { $as_echo "$as_me:${as_lineno-$LINENO}: WARNING: IME support is required for IBus." >&5
diff --git a/configure.ac b/configure.ac
index 6d11977e7..387e73edd 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2715,14 +2715,11 @@ AS_HELP_STRING([--enable-dbus], [enable D-Bus support [[default=yes]]]),
     if test x$enable_dbus = xyes; then
         PKG_CHECK_MODULES([DBUS], [dbus-1], have_dbus=yes, have_dbus=no)
         save_CPPFLAGS="$CPPFLAGS"
-        save_CFLAGS="$CFLAGS"
         CPPFLAGS="$save_CPPFLAGS $DBUS_CFLAGS"
-        CFLAGS="$save_CFLAGS $DBUS_CFLAGS"
         AC_CHECK_HEADER(dbus/dbus.h,
                         have_dbus_dbus_h_hdr=yes,
                         have_dbus_dbus_h_hdr=no)
         CPPFLAGS="$save_CPPFLAGS"
-        CFLAGS="$save_CFLAGS"
         if test x$have_dbus_dbus_h_hdr = xyes; then
             AC_DEFINE(HAVE_DBUS_DBUS_H, 1, [ ])
             EXTRA_CFLAGS="$EXTRA_CFLAGS $DBUS_CFLAGS"
@@ -2774,14 +2771,11 @@ AS_HELP_STRING([--enable-ibus], [enable IBus support [[default=yes]]]),
     if test x$enable_ibus = xyes; then
         PKG_CHECK_MODULES([IBUS], [ibus-1.0], have_ibus=yes, have_ibus=no)
         save_CPPFLAGS="$CPPFLAGS"
-        save_CFLAGS="$CFLAGS"
         CPPFLAGS="$save_CPPFLAGS $IBUS_CFLAGS"
-        CFLAGS="$save_CFLAGS $IBUS_CFLAGS"
         AC_CHECK_HEADER(ibus-1.0/ibus.h,
                         have_ibus_ibus_h_hdr=yes,
                         have_ibus_ibus_h_hdr=no)
         CPPFLAGS="$save_CPPFLAGS"
-        CFLAGS="$save_CFLAGS"
         if test x$have_ibus_ibus_h_hdr = xyes; then
             if test x$enable_ime != xyes; then
                 AC_MSG_WARN([IME support is required for IBus.])