When using MSVC set the subsystem to force minimal XP target OS.

Basically this makes the linker use the option /SUBSYSTEM, with its 4
combinations:

/SUBSYSTEM:WINDOWS,5.01
/SUBSYSTEM:CONSOLE,5.01
/SUBSYSTEM:WINDOWS,5.02
/SUBSYSTEM:CONSOLE,5.02

Where 5,01 is used for 32bit arch and 5,02 for 64bit this specifies XP as
a minimal targeted OS version.

https://blogs.msdn.microsoft.com/vcblog/2012/10/08/windows-xp-targeting-with-c-in-visual-studio-2012/

bootloader/wscript

@@ -619,6 +619,10 @@ def configure(ctx):
             # Use Unicode entry point wmain/wWinMain and wchar_t WinAPI
             ctx.env.append_value('CFLAGS', '-DUNICODE')
             ctx.env.append_value('CFLAGS', '-D_UNICODE')
+            # set XP target as minimal target OS ver. when using Windows w/MSVC
+            # https://blogs.msdn.microsoft.com/vcblog/2012/10/08/windows-xp-targeting-with-c-in-visual-studio-2012/
+            ctx.env.append_value('LINKFLAGS', '/SUBSYSTEM:CONSOLE,%s' % (
+                '5.01' if ctx.env.PYI_ARCH == '32bit' else '5.02'))
         else:
             # Use Visual C++ compatible alignment
             ctx.env.append_value('CFLAGS', '-mms-bitfields')
@@ -645,11 +649,19 @@ def configure(ctx):
         ctx.setenv(name, baseenv)  # Inherit from `baseenv`.
         ctx.env.append_value('DEFINES', 'WINDOWED')
 
-        if ctx.env.DEST_OS == 'win32' and ctx.env.CC_NAME != 'msvc':
-            # For MinGW disable console window on Windows - MinGW option
-            # TODO Is it necessary to have -mwindows for C and LINK flags?
-            ctx.env.append_value('LINKFLAGS', '-mwindows')
-            ctx.env.append_value('CFLAGS', '-mwindows')
+        if ctx.env.DEST_OS == 'win32':
+            if ctx.env.CC_NAME != 'msvc':
+                # For MinGW disable console window on Windows - MinGW option
+                # TODO Is it necessary to have -mwindows for C and LINK flags?
+                ctx.env.append_value('LINKFLAGS', '-mwindows')
+                ctx.env.append_value('CFLAGS', '-mwindows')
+            else:
+                _link_flags = ctx.env._get_list_value_for_modification('LINKFLAGS')
+                _subsystem = [x for x in _link_flags if x.startswith('/SUBSYSTEM:')]
+                for parameter in _subsystem:
+                    _link_flags.remove(parameter)
+                ctx.env.append_value('LINKFLAGS', '/SUBSYSTEM:WINDOWS,%s' % (
+                    '5.01' if ctx.env.PYI_ARCH == '32bit' else '5.02'))
         elif ctx.env.DEST_OS == 'darwin':
             # To support catching AppleEvents and running as ordinary OSX GUI
             # app, we have to link against the Carbon framework.