cgraph: use GVDLL instead of _WIN32 to control storage-class attributes in csprint.h

Towards https://gitlab.com/graphviz/graphviz/-/issues/2173.

diff --git a/lib/cgraph/sprint.h b/lib/cgraph/sprint.h
index def468c4636bd49c9c8a530f4e7000a79630b6bf..584313d27441b5358d3ee8d6ea8dacdfd34a6e91 100644 (file)
--- a/lib/cgraph/sprint.h
+++ b/lib/cgraph/sprint.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#ifdef _WIN32
+#ifdef GVDLL
 #ifdef EXPORT_CGRAPH
 #define DECLSPEC __declspec(dllexport)
 #else