* nt/mingw-cfg.site (gl_cv_func_free_preserves_errno): Set to
"yes" to avoid compiling Gnulib's free.c in the MinGW build.
# We don't want to build Emacs so it depends on bcrypt.dll, since then
# it will refuse to start on systems where that DLL is absent.
gl_cv_lib_assume_bcrypt=no
+# Don't build the Gnulib free.c: it is not needed, since the w32
+# implementation of 'free' doesn't touch errno, and it emits a
+# compilation warning.
+gl_cv_func_free_preserves_errno=yes