code breaks when fmt is external, so am using fmts implementation only

include/spdlog/details/attr_composer.h

@@ -8,7 +8,7 @@ namespace details {
 
 inline void scramble(std::string& dst, string_view_t s)
 {
-    if (s.empty())
+    if (s.size() == 0)
         return;
 
     auto start = s.data();

include/spdlog/fmt/bundled/core.h

@@ -474,8 +474,6 @@ template <typename Char> class basic_string_view {
   /** Returns the string size. */
   constexpr auto size() const noexcept -> size_t { return size_; }
 
-  constexpr auto empty() const noexcept -> bool { return size_ == 0; }
-
   constexpr auto begin() const noexcept -> iterator { return data_; }
   constexpr auto end() const noexcept -> iterator { return data_ + size_; }