[libdivide] Make all inline function constexpr Change-Id: I7a987e0859444515a6e5d31c4115f28035456811

diff --git a/libdivide.h b/libdivide.h
index 4d0720a..23f8119 100644
--- a/libdivide.h
+++ b/libdivide.h

@@ -98,14 +98,14 @@
 // We need both the attribute and keyword to avoid "might not be inlineable" warnings.
 #ifdef __has_attribute
 #if __has_attribute(always_inline)
-#define LIBDIVIDE_INLINE __attribute__((always_inline)) inline
+#define LIBDIVIDE_INLINE constexpr __attribute__((always_inline)) inline
 #endif
 #endif
 #ifndef LIBDIVIDE_INLINE
 #ifdef _MSC_VER
-#define LIBDIVIDE_INLINE __forceinline
+#define LIBDIVIDE_INLINE constexpr __forceinline
 #else
-#define LIBDIVIDE_INLINE inline
+#define LIBDIVIDE_INLINE constexpr inline
 #endif
 #endif
 
@@ -139,7 +139,7 @@
 
 // Use https://en.cppreference.com/w/cpp/feature_test#cpp_constexpr
 #if defined(__cpp_constexpr) && (__cpp_constexpr >= 201304L)
-#define LIBDIVIDE_CONSTEXPR constexpr LIBDIVIDE_INLINE
+#define LIBDIVIDE_CONSTEXPR LIBDIVIDE_INLINE
 
 // Supposedly, MSVC might not implement feature test macros right:
 // https://stackoverflow.com/questions/49316752/feature-test-macros-not-working-properly-in-visual-c
@@ -147,7 +147,7 @@
 // 2017 15.0 (for extended constexpr support:
 // https://learn.microsoft.com/en-us/cpp/overview/visual-cpp-language-conformance?view=msvc-170)
 #elif (defined(_MSC_VER) && _MSC_VER >= 1910) && (defined(_MSVC_LANG) && _MSVC_LANG >= 201402L)
-#define LIBDIVIDE_CONSTEXPR constexpr LIBDIVIDE_INLINE
+#define LIBDIVIDE_CONSTEXPR LIBDIVIDE_INLINE
 
 #else
 #define LIBDIVIDE_CONSTEXPR LIBDIVIDE_INLINE