Manage FreeType symbol visibility using platform specific FT_EXPORT

third_party/freetype/include/freetype-custom-config/ftoption.h

Index: third_party/freetype/include/freetype-custom-config/ftoption.h
diff --git a/third_party/freetype/include/freetype-custom-config/ftoption.h b/third_party/freetype/include/freetype-custom-config/ftoption.h
index e2d22a877e5b7a40d5cf39c853b3fe42326b1bde..b481d8cfee784d1f41b0f4a7deac03e9dfd0ec22 100644
--- a/third_party/freetype/include/freetype-custom-config/ftoption.h
+++ b/third_party/freetype/include/freetype-custom-config/ftoption.h
@@ -309,9 +309,13 @@ FT_BEGIN_HEADER
   /*   Do not #undef these macros here since the build system might define */
   /*   them for certain configurations only.                               */
   /*                                                                       */
-/* #define FT_EXPORT(x)      extern x */
-/* #define FT_EXPORT_DEF(x)  x */
-
+#if defined(_WIN32)
+#define FT_EXPORT(x)     __declspec(dllexport) x
+#define FT_EXPORT_DEF(x) __declspec(dllexport) x

[bungeman-skia, 2017/03/10 17:02:56]

How are you getting away with using only dllexport and not dllimport? Are all
the trybots non-component builds? Usually on Windows one sees something more
like https://lists.nongnu.org/archive/html/freetype/2009-05/msg00004.html which
also takes into account that in a non-component build you don't want to export
anything (Chromium doesn't want to expose the FreeType symbols in a
non-component build if it can be avoided).

[drott, 2017/03/13 10:17:37]

Thanks for pointing this out. I am not very familiar with Windows linking, but
according to https://msdn.microsoft.com/en-us/library/aa271769(v=vs.60).aspx I
can get away without dllimport at the expense of an extra redirect thunk, if I
understood correctly. In the updated patch I try to match dllexport/dllimport if
it's a component build and don't add any extra qualifications when it's static
linkage. On non Windows, I add the gcc-style visibility attribute.

+#else
+#define FT_EXPORT(x)     __attribute__((visibility ("default"))) x
+#define FT_EXPORT_DEF(x) __attribute__((visibility ("default"))) x
+#endif
 
   /*************************************************************************/
   /*                                                                       */