cmake: Fix usage of CMAKE_DEPENDENT_OPTION

CMAKE_DEPENDENT_OPTION takes a value argument, but as a macro function
it will read a variable name as the name and not the value. For
YUZU_USE_BUNDLED_QT, ensure that we are reading the value of MSVC. For
YUZU_ALLOW_SYSTEM_SDL2, CMAKE_DEPENDENT_OPTION is redundant here anyway
as we don't use that path on any toolchain by default.

CMakeLists.txt

@@ -13,11 +13,11 @@ project(yuzu)
 option(ENABLE_SDL2 "Enable the SDL2 frontend" ON)
 CMAKE_DEPENDENT_OPTION(YUZU_USE_BUNDLED_SDL2 "Download bundled SDL2 binaries" ON "ENABLE_SDL2;MSVC" OFF)
 # On Linux system SDL2 is likely to be lacking HIDAPI support which have drawbacks but is needed for SDL motion
-CMAKE_DEPENDENT_OPTION(YUZU_ALLOW_SYSTEM_SDL2 "Try using system SDL2 before fallling back to one from externals" NOT UNIX "ENABLE_SDL2" OFF)
+option(YUZU_ALLOW_SYSTEM_SDL2 "Try using system SDL2 before fallling back to one from externals" OFF)
 
 option(ENABLE_QT "Enable the Qt frontend" ON)
 option(ENABLE_QT_TRANSLATION "Enable translations for the Qt frontend" OFF)
-CMAKE_DEPENDENT_OPTION(YUZU_USE_BUNDLED_QT "Download bundled Qt binaries" MSVC "ENABLE_QT" OFF)
+CMAKE_DEPENDENT_OPTION(YUZU_USE_BUNDLED_QT "Download bundled Qt binaries" "${MSVC}" "ENABLE_QT" OFF)
 
 option(ENABLE_WEB_SERVICE "Enable web services (telemetry, etc.)" ON)