move append_float_length specialization to the header

format.cc

@@ -1132,24 +1132,6 @@ template int fmt::internal::CharTraits<wchar_t>::format_float(
     wchar_t *buffer, std::size_t size, const wchar_t *format,
     unsigned width, int precision, long double value);
 
-template <> template <> char* fmt::BasicWriter<char>::append_float_length<float>( char* format_ptr) { return format_ptr; }
-template <> template <> wchar_t* fmt::BasicWriter<wchar_t>::append_float_length<float>( wchar_t* format_ptr) { return format_ptr; }
-
-template <> template <> char* fmt::BasicWriter<char>::append_float_length<double>( char* format_ptr) { return format_ptr; }
-template <> template <> wchar_t* fmt::BasicWriter<wchar_t>::append_float_length<double>( wchar_t* format_ptr) { return format_ptr; }
-
-template <> template <> char* fmt::BasicWriter<char>::append_float_length<long double>( char* format_ptr)
-{
-    *format_ptr++ = 'L';
-    return format_ptr;
-}
-
-template <> template <> wchar_t* fmt::BasicWriter<wchar_t>::append_float_length<long double>( wchar_t* format_ptr)
-{
-    *format_ptr++ = 'L';
-    return format_ptr;
-}
-
 #if _MSC_VER
 # pragma warning(pop)
 #endif

format.h

@@ -1494,7 +1494,7 @@ class BasicWriter {
   void operator<<(typename internal::CharTraits<Char>::UnsupportedStrType);
 
   template<typename T>
-  Char* append_float_length(Char* format_ptr);
+  Char* append_float_length(Char* format_ptr) { return format_ptr; }
 
   friend class internal::ArgFormatter<Char>;
   friend class internal::PrintfFormatter<Char>;
@@ -1981,6 +1981,16 @@ void BasicWriter<Char>::write_double(
   }
 }
 
+template <> template <> inline char* BasicWriter<char>::append_float_length<long double>( char* format_ptr) {
+    *format_ptr++ = 'L';
+    return format_ptr;
+}
+
+template <> template <> inline wchar_t* BasicWriter<wchar_t>::append_float_length<long double>( wchar_t* format_ptr) {
+    *format_ptr++ = 'L';
+    return format_ptr;
+}
+
 /**
   \rst
   This template provides operations for formatting and writing data into