Fixes for deprecated std::basic_string::reserve()

CHANGES.current

@@ -7,6 +7,23 @@ the issue number to the end of the URL: https://github.com/swig/swig/issues/
 Version 4.1.0 (in progress)
 ===========================
 
+2022-07-30: wsfulton
+            C++20 has deprecated std::basic_string<>::reserve() and the C++11 method
+            std::basic_string<>::shrink_to_fit() is a replacement that can be used.
+            std_string.i and std_wstring.i provided wrappers for reserve with the following
+            template instantiations:
+
+              %template(string) std::basic_string<char>;
+              %template(wstring) std::basic_string<wchar_t>;
+
+            The reserve method is no longer wrapped, however the shrink_to_fit() method
+            can be used as an alternative from the target language (the generated wrappers
+            call reserve() instead if C++<=20).
+
+            Note that std::basic_string<>::reserve(size_t n) is still wrapped unchanged.
+
+            *** POTENTIAL INCOMPATIBILITY ***
+
 2022-07-30: wsfulton
             [Tcl] Add support for std::unique_ptr in std_unique_ptr.i.
             Add support for std::auto_ptr in std_auto_ptr.i.

Examples/test-suite/python/li_std_string_extra_runme.py

@@ -15,6 +15,11 @@ if li_std_string_extra.test_value(x) != x:
 if li_std_string_extra.test_const_reference(x) != x:
     raise RuntimeError("bad string mapping")
 
+s = li_std_string_extra.string("1234567890")
+size = s.size()
+if size != 10:
+    raise "Incorrect size"
+s.shrink_to_fit()
 
 s = li_std_string_extra.string("he")
 #s += "ll"

Lib/std/std_basic_string.i

@@ -55,7 +55,16 @@ namespace std {
 
     size_type capacity() const;
 
-    void reserve(size_type __res_arg = 0);
+    void reserve(size_type __res_arg);
+    %extend {
+      void shrink_to_fit() {
+        %#if __cplusplus >= 202002L
+          self->shrink_to_fit();
+        %#else
+          self->reserve();
+        %#endif
+      }
+    }
 
 
     // Modifiers: