A klammer set's Python speaks through the log

Assembled from development commit d5f9c20b94b3. Since 5c29da5: a print() in
@eval, or in any Python a klammer set runs, is a log line -- on the
error stream under the command's name at -v 1, silent otherwise, never
in the document -- and K_log(level, text) is the builtin behind it; a
Python script using the binding keeps its own stdout. Previously such
output was lost, or on a terminal landed in the document.

mac/command.cpp

@@ -9,6 +9,7 @@
 #include <tuple>
 
 #include "argv.h"
+#include "eval_python.h"
 #include "file.h"
 #include "log.h"
 #include "machine.h"
@@ -73,6 +74,9 @@ void set_verbose_level(int argc, char* argv[])
     args.opt("v", "'verbosity'", "level", "0", "'verbosity'");
     args.parse(argc, argv, false);
     verbose_level = args.as_verbosity("v");
+    // A klammer set's Python speaks through the log (eval_python.h): the
+    // commands only -- the binding leaves the host's sys.stdout alone.
+    set_python_output_to_log(true);
 #ifdef _WIN32
     if (console_output_cp != 0 && console_output_cp != CP_UTF8) {
         K::log(1, "Console output code page set to UTF-8 for this run (was "