remove third_party/libwebp/webp/config.h

This doesn't appear to have any effect.
It's not mentioned in our build configuration anywhere,
nor is third_party/libwebp/webp on any include path.

Bug: skia:4037

Change-Id: I41710fe5e82bb97946e64d5f975c09c8ba21dc0d
Reviewed-on: https://skia-review.googlesource.com/99860
Reviewed-by: Leon Scroggins <scroggo@google.com>
Commit-Queue: Mike Klein <mtklein@chromium.org>
diff --git a/third_party/libwebp/webp/config.h b/third_party/libwebp/webp/config.h
deleted file mode 100644
index 518f18f..0000000
--- a/third_party/libwebp/webp/config.h
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
- * Copyright 2015 Google, Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
-
-// FIXME: Workaround for https://bug.skia.org/4037
-// Some of our test machines have an older version of clang that does not
-// have
-//    __builtin_bswap16
-//
-// But libwebp expects the builtin. We can change that by using this config.h
-// file, which replaces the checks in endian_inl.h to decide whether we have
-// particular builtins.
-
-#ifdef __builtin_bswap64
-    #define HAVE_BUILTIN_BSWAP64
-#endif
-
-#ifdef __builtin_bswap32
-    #define HAVE_BUILTIN_BSWAP32
-#endif
-
-#ifdef __builtin_bswap16
-    #define HAVE_BUILTIN_BSWAP16
-#endif