Update client_cvar_value.h

Author: RexusOhm

src/client_cvar_value.h

@@ -26,6 +26,32 @@
 #include <string>
 #include <array>
 
+#if defined _WIN32 || defined __CYGWIN__
+  #ifdef BUILDING_DLL
+    #ifdef __GNUC__
+      #define DLL_PUBLIC __attribute__ ((dllexport))
+    #else
+      #define DLL_PUBLIC __declspec(dllexport) // Note: actually gcc seems to also supports this syntax.
+    #endif
+  #else
+    #ifdef __GNUC__
+      #define DLL_PUBLIC __attribute__ ((dllimport))
+    #else
+      #define DLL_PUBLIC __declspec(dllimport) // Note: actually gcc seems to also supports this syntax.
+    #endif
+  #endif
+  #define DLL_LOCAL
+#else
+  #if __GNUC__ >= 4
+    #define DLL_PUBLIC __attribute__ ((visibility ("default")))
+    #define DLL_LOCAL  __attribute__ ((visibility ("hidden")))
+  #else
+    #define DLL_PUBLIC
+    #define DLL_LOCAL
+  #endif
+#endif
+#define EXPORTDLL extern "C" DLL_PUBLIC
+
 class ClientCvarValue final : public ISmmPlugin, public IMetamodListener, public IClientCvarValue
 {
 public: