Fixed build warning.
diff --git a/imgui.cpp b/imgui.cpp
index 7480a8d..6f90d94 100644
--- a/imgui.cpp
+++ b/imgui.cpp
@@ -14569,7 +14569,7 @@
 
     // Basic info
     Text("Dear ImGui %s", GetVersion());
-    if (g.ContextName[0] != NULL)
+    if (g.ContextName[0] != 0)
     {
         SameLine();
         Text("(Context Name: \"%s\")", g.ContextName);