From 7f8060d5b280eac9786f92ac74d263cc8359c5ed Mon Sep 17 00:00:00 2001
From: Christian Blichmann <cblichmann@users.noreply.github.com>
Date: Tue, 7 Jan 2025 23:59:12 +0100
Subject: [PATCH] fix: Compatibility with external fmtlib 11.1.1 (#3312)

Include fmtlib's `xchar` header to include `fmt::basic_format_string`.
Otherwise, compilation with an external fmtlib 11.1.1 fails with

```
In file included from include/spdlog/spdlog.h:12:
include/spdlog/common.h:369:49: error: no template named 'basic_format_string' in namespace 'fmt'; did you mean 'std::basic_format_string'?
  369 | inline fmt::basic_string_view<T> to_string_view(fmt::basic_format_string<T, Args...> fmt) {
      |                                                 ^~~~~
```

Signed-off-by: Christian Blichmann <cblichmann@google.com>
---
 include/spdlog/fmt/fmt.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/spdlog/fmt/fmt.h b/include/spdlog/fmt/fmt.h
index 7fa6b093..2f09c15e 100644
--- a/include/spdlog/fmt/fmt.h
+++ b/include/spdlog/fmt/fmt.h
@@ -27,4 +27,5 @@
 #else  // SPDLOG_FMT_EXTERNAL is defined - use external fmtlib
     #include <fmt/core.h>
     #include <fmt/format.h>
+    #include <fmt/xchar.h>
 #endif