diff --git a/lib/wchar.in.h b/lib/wchar.in.h
--- a/lib/wchar.in.h
+++ b/lib/wchar.in.h
@@ -152,7 +152,11 @@
 _GL_EXTERN_C void free (void *);
 # define free rpl_free
 #endif
+#ifndef _MSC_VER
+/* On MSVC the CRT declares free with __declspec(dllimport) linkage.
+   A plain forward declaration here would conflict (C4273).  */
 _GL_EXTERN_C void free (void *);
+#endif
 
 /* Convert a single-byte character to a wide character.  */
 #if @GNULIB_BTOWC@