From b0ad64743dbfcee25cd03811f37a29e69715a07c Mon Sep 17 00:00:00 2001
From: Shujian Qian <shujian.qian@outlook.com>
Date: Fri, 18 Aug 2023 18:48:12 -0400
Subject: [PATCH] Modify the condition of SPDLOG_CONSTEXPR_FUNC to match that
 of fmt

fix the issue where constexpr function in spdlog may call non-constexpr function in the bundled fmt because FMT_USE_CONSTEXPR is not defined.
---
 include/spdlog/common.h | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/include/spdlog/common.h b/include/spdlog/common.h
index c46c1531..2c98789f 100644
--- a/include/spdlog/common.h
+++ b/include/spdlog/common.h
@@ -65,15 +65,21 @@
 #if defined(_MSC_VER) && (_MSC_VER < 1900)
     #define SPDLOG_NOEXCEPT _NOEXCEPT
     #define SPDLOG_CONSTEXPR
-    #define SPDLOG_CONSTEXPR_FUNC inline
 #else
     #define SPDLOG_NOEXCEPT noexcept
     #define SPDLOG_CONSTEXPR constexpr
-    #if __cplusplus >= 201402L
-        #define SPDLOG_CONSTEXPR_FUNC constexpr
-    #else
-        #define SPDLOG_CONSTEXPR_FUNC inline
-    #endif
+#endif
+
+#ifndef __has_feature
+#    define __has_feature(x) 0
+#endif
+
+#if (__has_feature(cxx_relaxed_constexpr) || (defined(_MSC_VER) && (_MSC_VER >= 1912)) ||                                                  \
+     (defined(__GNUC__) && __GNUC__ >= 6 && defined(__cplusplus) && __cplusplus >= 201402L)) &&                                            \
+    !defined(__ICL) && !defined(__INTEL_COMPILER) && !defined(__NVCC__)
+    #define SPDLOG_CONSTEXPR_FUNC constexpr
+#else
+    #define SPDLOG_CONSTEXPR_FUNC inline
 #endif
 
 #if defined(__GNUC__) || defined(__clang__)