win32: Use Console subsystem on debug builds

Using the console subsystem allows to use std.log and other console-related operations, which is very useful for logging. This comes at the cost of the executable opening a new console window (cmdhost.exe) but this is not deranging given it's only for Debug mode builds.

build_capy.zig

@@ -21,7 +21,10 @@ pub fn install(step: *std.build.LibExeObjStep, comptime prefix: []const u8) !voi
                 else => {},
             };
 
-            step.subsystem = .Windows;
+            switch (step.build_mode) {
+                .Debug => step.subsystem = .Console,
+                else => step.subsystem = .Windows,
+            }
             step.linkSystemLibrary("comctl32");
             step.linkSystemLibrary("gdi32");
             step.linkSystemLibrary("gdiplus");