Add fmtlib::fmt backport of C++20 std::format

Because I'm tired of waiting for std::format.

.gitmodules

@@ -40,3 +40,6 @@
 [submodule "external/date"]
 	path = external/date
 	url = https://github.com/HowardHinnant/date.git
+[submodule "external/fmt"]
+	path = external/fmt
+	url = https://github.com/fmtlib/fmt.git

external/CMakeLists.txt

@@ -85,6 +85,7 @@ add_subdirectory(easylogging++ easyloggingpp)
 add_subdirectory(randomx EXCLUDE_FROM_ALL)
 add_subdirectory(fmt)
 add_subdirectory(date EXCLUDE_FROM_ALL)
+add_subdirectory(fmt)
 
 set(JSON_BuildTests OFF CACHE INTERNAL "")
 set(JSON_MultipleHeaders ON CACHE BOOL "") # Allows multi-header nlohmann use

src/common/CMakeLists.txt

@@ -68,6 +68,7 @@ target_link_libraries(common
     filesystem
     fmt::fmt
     date::date
+    fmt::fmt
   PRIVATE
     libunbound
     OpenSSL::SSL

src/daemon/rpc_command_executor.cpp

@@ -45,6 +45,7 @@
 #include <oxenmq/base32z.h>
 #include <fmt/core.h>
 #include <date/date.h>
+#include <fmt/core.h>
 
 #include <fstream>
 #include <ctime>
@@ -659,8 +660,8 @@ bool rpc_command_executor::print_connections() {
         info["current_download"].get<uint64_t>() / 1000.,
         info["avg_upload"].get<uint64_t>() / 1000.,
         info["current_upload"].get<uint64_t>() / 1000.,
-        (info.value("localhost", false) ? "[LOCALHOST]" : ""),
-        (info.value("local_ip", false) ? "[LAN]" : ""));
+        info.value("localhost", false) ? "[LOCALHOST]" : "",
+        info.value("local_ip", false) ? "[LAN]" : "");
   }
 
   return true;