Move definition of FMT_USE_INT128 to core.h

include/fmt/core.h

@@ -195,6 +195,14 @@
 #  define FMT_USE_EXPERIMENTAL_STRING_VIEW
 #endif
 
+#ifdef FMT_USE_INT128
+// Do nothing.
+#elif defined(__SIZEOF_INT128__)
+#  define FMT_USE_INT128 1
+#else
+#  define FMT_USE_INT128 0
+#endif
+
 FMT_BEGIN_NAMESPACE
 
 // Implementations of enable_if_t and other types for pre-C++14 systems.

include/fmt/format.h

@@ -123,14 +123,6 @@ FMT_END_NAMESPACE
 #  endif
 #endif
 
-#ifdef FMT_USE_INT128
-// Do nothing.
-#elif defined(__SIZEOF_INT128__)
-#  define FMT_USE_INT128 1
-#else
-#  define FMT_USE_INT128 0
-#endif
-
 // __builtin_clz is broken in clang with Microsoft CodeGen:
 // https://github.com/fmtlib/fmt/issues/519
 #if (FMT_GCC_VERSION || FMT_HAS_BUILTIN(__builtin_clz)) && !FMT_MSC_VER