gvpack: mark 'gvplugin_neato_layout_LTX_library' as having C linkage

gvpack.c is currently compiled as C, so this symbol already has C linkage by
default. However an upcoming commit converts it to C++, which then results in
link failures due to this defaulting to C++ linkage. To pre-empt that, we note
its linkage explicitly for now. These guards will be removed in a future commit.

Gitlab: #2154

diff --git a/cmd/tools/gvpack.c b/cmd/tools/gvpack.c
index 0fad73b36a71f893d48a2d1abf1728149c1acb71..7caf6d75ee41573f7e99376e0129f049e35f8dda 100644 (file)
--- a/cmd/tools/gvpack.c
+++ b/cmd/tools/gvpack.c
@@ -29,11 +29,19 @@
 #include <stddef.h>
 #include <stdbool.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifdef GVDLL
   __declspec(dllimport)
 #endif
 extern gvplugin_library_t gvplugin_neato_layout_LTX_library;
 
+#ifdef __cplusplus
+}
+#endif
+
 lt_symlist_t lt_preloaded_symbols[] = {
 #ifdef GVDLL
        { "gvplugin_neato_layout_LTX_library", 0 },