diff --git a/LEGO1/library_msvc.h b/LEGO1/library_msvc.h
index 60f5988c..b0542e13 100644
--- a/LEGO1/library_msvc.h
+++ b/LEGO1/library_msvc.h
@@ -1,4 +1,4 @@
-#ifdef 0
+#if 0
 // For LEGO1 symbols only
 
 // aka `operator new`
diff --git a/LEGO1/library_smack.h b/LEGO1/library_smack.h
index 0967aeab..56d00db6 100644
--- a/LEGO1/library_smack.h
+++ b/LEGO1/library_smack.h
@@ -1,4 +1,4 @@
-#ifdef 0
+#if 0
 
 // LIBRARY: LEGO1 0x100cd782
 // LIBRARY: BETA10 0x1015fb82
diff --git a/LEGO1/tgl/d3drm/impl.h b/LEGO1/tgl/d3drm/impl.h
index 555d8432..9bf95668 100644
--- a/LEGO1/tgl/d3drm/impl.h
+++ b/LEGO1/tgl/d3drm/impl.h
@@ -1,3 +1,5 @@
+#ifndef TGL_D3DRM_IMPL_H
+#define TGL_D3DRM_IMPL_H
 
 #include "compat.h"
 #include "decomp.h"
@@ -819,3 +821,5 @@ inline D3DRMLIGHTTYPE Translate(LightType tglLightType)
 // IID_IDirect3DRMMeshBuilder
 
 } /* namespace TglImpl */
+
+#endif