CMakeLists: Define FMT_USE_USER_DEFINED_LITERALS=0

This disable a fmtlib feature that depends on a non-standard feature
for its implementation.

src/CMakeLists.txt

@@ -299,6 +299,8 @@ endif()
 if (CMAKE_SYSTEM_NAME STREQUAL "Windows")
     target_compile_definitions(dynarmic PRIVATE FMT_USE_WINDOWS_H=0)
 endif()
+# Disable this as it relies on a non-standard feature
+target_compile_definitions(dynarmic PRIVATE FMT_USE_USER_DEFINED_LITERALS=0)
 
 export(
     TARGETS   dynarmic boost fmt xbyak