diff --git a/gfx/ots/include/opentype-sanitiser.h b/gfx/ots/include/opentype-sanitiser.h
--- a/gfx/ots/include/opentype-sanitiser.h
+++ b/gfx/ots/include/opentype-sanitiser.h
@@ -1,15 +1,35 @@
 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef OPENTYPE_SANITISER_H_
 #define OPENTYPE_SANITISER_H_
 
+#if defined(_WIN32) || defined(__CYGWIN__)
+  #define OTS_DLL_IMPORT __declspec(dllimport)
+  #define OTS_DLL_EXPORT __declspec(dllexport)
+#else
+  #if __GNUC__ >= 4
+    #define OTS_DLL_IMPORT __attribute__((visibility ("default")))
+    #define OTS_DLL_EXPORT __attribute__((visibility ("default")))
+  #endif
+#endif
+
+#ifdef OTS_DLL
+  #ifdef OTS_DLL_EXPORTS
+    #define OTS_API OTS_DLL_EXPORT
+  #else
+    #define OTS_API OTS_DLL_IMPORT
+  #endif
+#else
+  #define OTS_API
+#endif
+
 #if defined(_WIN32)
 #include <stdlib.h>
 typedef signed char int8_t;
 typedef unsigned char uint8_t;
 typedef short int16_t;
 typedef unsigned short uint16_t;
 typedef int int32_t;
 typedef unsigned int uint32_t;
@@ -182,45 +202,45 @@ class OTSStream {
 // -----------------------------------------------------------------------------
 // Process a given OpenType file and write out a sanitised version
 //   output: a pointer to an object implementing the OTSStream interface. The
 //     sanitisied output will be written to this. In the even of a failure,
 //     partial output may have been written.
 //   input: the OpenType file
 //   length: the size, in bytes, of |input|
 // -----------------------------------------------------------------------------
-bool Process(OTSStream *output, const uint8_t *input, size_t length);
+bool OTS_API Process(OTSStream *output, const uint8_t *input, size_t length);
 
 // Signature of the function to be provided by the client in order to report errors.
 // The return type is a boolean so that it can be used within an expression,
 // but the actual value is ignored. (Suggested convention is to always return 'false'.)
 #ifdef __GCC__
 #define MSGFUNC_FMT_ATTR __attribute__((format(printf, 2, 3)))
 #else
 #define MSGFUNC_FMT_ATTR
 #endif
 typedef bool (*MessageFunc)(void *user_data, const char *format, ...)  MSGFUNC_FMT_ATTR;
 
 // Set a callback function that will be called when OTS is reporting an error.
-void SetMessageCallback(MessageFunc func, void *user_data);
+void OTS_API SetMessageCallback(MessageFunc func, void *user_data);
 
 enum TableAction {
   TABLE_ACTION_DEFAULT,  // Use OTS's default action for that table
   TABLE_ACTION_SANITIZE, // Sanitize the table, potentially droping it
   TABLE_ACTION_PASSTHRU, // Serialize the table unchanged
   TABLE_ACTION_DROP      // Drop the table
 };
 
 // Signature of the function to be provided by the client to decide what action
 // to do for a given table.
 typedef TableAction (*TableActionFunc)(uint32_t tag, void *user_data);
 
 // Set a callback function that will be called when OTS needs to decide what to
 // do for a font table.
-void SetTableActionCallback(TableActionFunc func, void *user_data);
+void OTS_API SetTableActionCallback(TableActionFunc func, void *user_data);
 
 // Force to disable debug output even when the library is compiled with
 // -DOTS_DEBUG.
 void DisableDebugOutput();
 
 // Enable WOFF2 support(experimental).
 void EnableWOFF2();