Fixes and tweaks for C++ API reference docs generation

Source/Engine/Platform/Android/AndroidFile.h

@@ -2,7 +2,7 @@
 
 #pragma once
 
-#if PLATFORM_UNIX
+#if PLATFORM_ANDROID
 
 #include "Engine/Platform/Unix/UnixFile.h"
 

Source/Engine/Platform/Linux/IncludeX11.h

@@ -2,6 +2,8 @@
 
 #pragma once
 
+#if PLATFORM_LINUX
+
 // Hide warning from old headers
 #define register
 
@@ -38,3 +40,5 @@ namespace X11
 #undef Status
 #undef True
 #undef False
+
+#endif

Source/Engine/Platform/Windows/ComPtr.h

@@ -2,6 +2,8 @@
 
 #pragma once
 
+#if PLATFORM_WINDOWS
+
 #include "Engine/Core/Templates.h"
 #include "../Win32/IncludeWindowsHeaders.h"
 
@@ -332,3 +334,5 @@ bool operator<(const ComPtr<T>& a, const ComPtr<U>& b)
     static_assert(__is_base_of(T, U) || __is_base_of(U, T), "'T' and 'U' pointers must be comparable");
     return a.Get() < b.Get();
 }
+
+#endif