Make clang happy, fix VS 2022 generator name

appveyor.yml

@@ -66,7 +66,7 @@ environment:
       BUILD_EXAMPLE: 'OFF'
       USE_STD_FORMAT: 'OFF'
       APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
-    - GENERATOR: '"Visual Studio 16 2022" -A x64'
+    - GENERATOR: '"Visual Studio 17 2022" -A x64'
       BUILD_TYPE: Release
       BUILD_SHARED: 'ON'
       WCHAR: 'OFF'

include/spdlog/details/fmt_helper.h

@@ -57,7 +57,7 @@ inline void append_int(T n, memory_buf_t &dest)
 #endif
 
 template<typename T>
-SPDLOG_CONSTEXPR unsigned int count_digits_fallback(T n)
+SPDLOG_CONSTEXPR_FUNC unsigned int count_digits_fallback(T n)
 {
     // taken from fmt.
     unsigned int count = 1;