Add 'console' command line argument

This opens a console window on Windows but does nothing anywhere else. Overrides 'redirect'.

Useful on Windows because the only way to access standard streams there is by tail -f'ing stdout/err.txt.

README.md

@@ -124,5 +124,6 @@ Command Line
 | `disable-network`     | Disables internet connections                    |                                             |
 | `disable-bluescreen`  | Disable bluescreen handler                       |                                             |
 | `redirect`            | Redirects output to stdout.txt / stderr.txt      |                                             |
+| `console`             | Redirects output to a new console on Windows     |                                             |
 | `cafile:CAFILE`       | Set certificate bundle path                      | `cafile:/etc/ssl/certs/ca-certificates.crt` |
 | `capath:CAPATH`       | Set certificate directory path                   | `capath:/etc/ssl/certs`                     |

src/PowderToy.cpp

@@ -380,7 +380,11 @@ int Main(int argc, char *argv[])
 	}
 
 	auto redirectStd = prefs.Get("RedirectStd", false);
-	if (true_arg(arguments["redirect"]) || redirectStd)
+	if (true_arg(arguments["console"]))
+	{
+		Platform::AllocConsole();
+	}
+	else if (true_arg(arguments["redirect"]) || redirectStd)
 	{
 		FILE *new_stdout = freopen("stdout.log", "w", stdout);
 		FILE *new_stderr = freopen("stderr.log", "w", stderr);

src/common/platform/Platform.h

@@ -74,6 +74,7 @@ namespace Platform
 	std::optional<std::vector<String>> StackTrace();
 
 	void MarkPresentable();
+	void AllocConsole();
 }
 
 extern "C" int Main(int argc, char *argv[]);

src/common/platform/Posix.cpp

@@ -150,4 +150,8 @@ std::vector<ByteString> DirectoryList(ByteString directory)
 	closedir(directoryHandle);
 	return directoryList;
 }
+
+void AllocConsole()
+{
+}
 }

src/common/platform/Windows.cpp

@@ -10,6 +10,7 @@
 #include <windows.h>
 #include <crtdbg.h>
 #include <memory>
+#include <cstdlib>
 
 namespace Platform
 {
@@ -409,4 +410,14 @@ void SetupCrt()
 		std::cerr << "failed to set codepage to utf-8, expect breakage" << std::endl;
 	}
 }
+
+void AllocConsole()
+{
+	if (!::AllocConsole())
+	{
+		return;
+	}
+	freopen("CONOUT$", "w", stdout);
+	freopen("CONOUT$", "w", stderr);
+}
 }