Revert "configure.ac: Allow user to disable gflags"

configure.ac

@@ -136,16 +136,16 @@ AC_ARG_WITH(gflags, AS_HELP_STRING[--with-gflags=GFLAGS_DIR],
   CFLAGS="$CFLAGS $GFLAGS_CFLAGS"
   LIBS="$LIBS $GFLAGS_LIBS"
 )
-
-AS_IF([test "x$with_gflags" != xno],
-  [AC_CHECK_LIB(gflags, main,
-    [AC_DEFINE(HAVE_LIB_GFLAGS, 1, [Define if you have Google gflags library])
-     if test x"$GFLAGS_LIBS" = x""; then
-       GFLAGS_LIBS="-lgflags"
-     fi
-     ac_cv_have_libgflags=1],
-    AC_MSG_FAILURE([gflags test failed (--without-gflags to disable)]))],
-  ac_cv_have_libgflags=0)
+AC_CHECK_LIB(gflags, main, ac_cv_have_libgflags=1, ac_cv_have_libgflags=0)
+if test x"$ac_cv_have_libgflags" = x"1"; then
+  AC_DEFINE(HAVE_LIB_GFLAGS, 1, [define if you have google gflags library])
+  if test x"$GFLAGS_LIBS" = x""; then
+    GFLAGS_LIBS="-lgflags"
+  fi
+else
+  GFLAGS_CFLAGS=
+  GFLAGS_LIBS=
+fi
 CFLAGS="$SAVE_CFLAGS"
 LIBS="$SAVE_LIBS"