$NetBSD$

https://skia-review.googlesource.com/c/skia/+/310856

--- third_party/skia/third_party/libsdl/BUILD.gn.orig	2020-07-15 19:01:41.000000000 +0000
+++ third_party/skia/third_party/libsdl/BUILD.gn
@@ -125,7 +125,7 @@ third_party("libsdl") {
     ]
   }
 
-  if (is_linux) {
+  if (is_linux || is_bsd) {
     sources += [
       "../externals/sdl/src/filesystem/unix/SDL_sysfilesystem.c",
       "../externals/sdl/src/render/opengl/SDL_render_gl.c",