Add ConvertColorCursors to CMake, port to *nix

- Includes WindowsUnicodeToolShim.h.
- Replaces sprintf_s() with std::ostringstream.
- Replaces fopen_s() with fopen_utf8().
- Switches to the toolMain() wrapper, which is a no-op on except on
  Windows, where it should improve Unicode support, though I can't test
  that on my end.
- Replaces \ with / in paths, which should still be Windows-compatible.

CMakeLists.txt

@@ -472,5 +472,21 @@ if(FREETYPE_FOUND)
 	target_link_libraries(GenerateFonts PortabilityLayer GpFontHandler_FreeType2)
 endif()
 
+add_executable(ConvertColorCursors
+	ConvertColorCursors/ConvertColorCursors.cpp
+	AerofoilPortable/GpAllocator_C.cpp
+	stb/stb_image_write.c
+	WindowsUnicodeToolShim/UnixUnicodeToolShim.cpp
+	)
+target_include_directories(ConvertColorCursors PRIVATE
+	Common
+	GpCommon
+	PortabilityLayer
+	AerofoilPortable
+	stb
+	WindowsUnicodeToolShim
+	)
+target_link_libraries(ConvertColorCursors PortabilityLayer)
+
 
 install (TARGETS ${EXECNAME})