Disable MSVC warnings about implicit conversion

Implicit conversion warnings happen all over the codebase, but there's
no reason to warn on all of them, and adding casts everywhere is
annoying to read and patently unnecessary.

MSVC is the only compiler that has this warning (GCC even on -Wall
-Wextra doesn't warn about implicit conversions), so disable it for
MSVC.

desktop_version/CMakeLists.txt

@@ -225,6 +225,11 @@ IF(SUPPORTS_IMPLICIT_FALLTHROUGH)
 	TARGET_COMPILE_OPTIONS(VVVVVV PRIVATE -Werror=implicit-fallthrough)
 ENDIF()
 
+IF(MSVC)
+	# Disable MSVC warnings about implicit conversion
+	TARGET_COMPILE_OPTIONS(VVVVVV PRIVATE /wd4244)
+ENDIF()
+
 SET_PROPERTY(TARGET VVVVVV PROPERTY CXX_STANDARD 98)
 SET_PROPERTY(TARGET VVVVVV PROPERTY CXX_EXTENSIONS FALSE)