gvc++: use GVDLL instead of _WIN32 to control storage-class attributes in GVContext.h

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

diff --git a/lib/gvc++/GVContext.h b/lib/gvc++/GVContext.h
index 4b960745907dcdb2d184bc92c52dba2ed15c908a..62d10edb5311143be11679590387d4665a8fa2d7 100644 (file)
--- a/lib/gvc++/GVContext.h
+++ b/lib/gvc++/GVContext.h
@@ -4,7 +4,7 @@
 
 #include <gvc/gvc.h>
 
-#ifdef _WIN32
+#ifdef GVDLL
 #if gvc___EXPORTS // CMake's substitution of gvc++_EXPORTS
 #define GVCONTEXT_API __declspec(dllexport)
 #else