fmt::fmt => fmt, to use system lib

Index: Source/Core/Common/CMakeLists.txt
--- Source/Core/Common/CMakeLists.txt.orig
+++ Source/Core/Common/CMakeLists.txt
@@ -132,7 +132,7 @@ target_link_libraries(common
 PUBLIC
   ${CMAKE_THREAD_LIBS_INIT}
   enet
-  fmt::fmt
+  fmt
   ${MBEDTLS_LIBRARIES}
 
 PRIVATE
