Add <lol/format> to ensure std::format is available

.gitmodules

@@ -31,3 +31,9 @@
 	branch = lol
 	update = merge
 	upstream = https://github.com/CLIUtils/CLI11
+
+[submodule "include/lol/3rdparty/fmt"]
+	path = include/lol/3rdparty/fmt
+	url = https://github.com/fmtlib/fmt
+	branch = master
+	update = merge

README.md

@@ -28,6 +28,7 @@ The header-only part of the Lol Engine framework.
 | `<lol/cli>`       | command-line parsing (imported from [cliutils/cli11](https://github.com/CLIUtils/CLI11)) | |
 | `<lol/dialogs>`   | portable file dialogs (imported from [samhocevar/portable-file-dialogs](https://github.com/samhocevar/portable-file-dialogs)) | |
 | `<lol/file>`      | file reading utilities | ● `lol::read(filename, data)` for any `std::string` or `std::vector`<br>● `lol::write(filename, data)` |
+| `<lol/format>`    | ensure `std::format` is available, using a fallback if necessary | |
 | `<lol/msg>`       | simple message logging | ● `lol::msg::info("hello\n");`<br>● `lol::msg::debug("%d %d\n", x, y);`<br>● also `lol::msg::error`, `lol::msg::warn` |
 | `<lol/thread>`    | threading and timing | ● `lol::thread`<br>● `lol::queue<int, 200>` (thread-safe FIFO queue)<br>● `lol::timer` (high precision timer) |
 | `<lol/unit_test>` | unit test framework | |

include/lol/3rdparty/fmt

@@ -0,0 +1 @@
+Subproject commit 71a4a8d47999e95f5e460eaf8cec894f60354a13

include/lol/format

@@ -0,0 +1,22 @@
+//
+//  Lol Engine
+//
+//  Copyright © 2010–2024 Sam Hocevar <sam@hocevar.net>
+//
+//  Lol Engine is free software. It comes without any warranty, to
+//  the extent permitted by applicable law. You can redistribute it
+//  and/or modify it under the terms of the Do What the Fuck You Want
+//  to Public License, Version 2, as published by the WTFPL Task Force.
+//  See http://www.wtfpl.net/ for more details.
+//
+
+#pragma once
+
+#include <version>
+#if defined _LIBCPP_HAS_NO_INCOMPLETE_FORMAT
+#   define FMT_HEADER_ONLY
+#   include "3rdparty/fmt/include/fmt/format.h"
+    namespace std { using fmt::format; }
+#else
+#   include <format>
+#endif

include/lol/private/base/string.h

@@ -21,7 +21,6 @@
 
 #include "../features.h"
 
-#include <format>    // std::format
 #include <vector>    // std::vector
 #include <string>    // std::basic_string
 #include <algorithm> // std::transform

include/lol/private/math/matrix.ipp

@@ -13,9 +13,9 @@
 #pragma once
 
 #include <cassert>
-#include <cmath>     // std::tan
-#include <algorithm> // std::max
-#include <format>    // std::format
+#include <cmath>      // std::tan
+#include <algorithm>  // std::max
+#include <lol/format> // std::format
 
 namespace lol
 {

include/lol/private/math/transform.ipp

@@ -13,7 +13,7 @@
 #pragma once
 
 #include <cmath>  // std::cos, std::sin
-#include <format> // std::format
+#include <lol/format> // std::format
 
 namespace lol
 {

include/lol/private/math/vector.ipp

@@ -12,7 +12,7 @@
 
 #pragma once
 
-#include <format> // std::format
+#include <lol/format> // std::format
 
 namespace lol
 {