diff --git a/BUILD.gn b/BUILD.gn
index 7e7658e..6885fc2 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -20,11 +20,14 @@
   ldflags = []
   include_dirs = [ "." ]
   defines = [
-    "OPJ_STATIC",
     "PNG_PREFIX",
     "PNG_USE_READ_MACROS",
   ]
 
+  if (!use_system_libopenjpeg2) {
+    defines += [ "OPJ_STATIC" ]
+  }
+
   if (pdf_enable_click_logging) {
     defines += [ "PDF_ENABLE_CLICK_LOGGING" ]
   }