shell.c defines macro HELP_COMMAND which collides with a like-named
macro from winuser.h. Avoid collision by sanitizing preprocessor
namespace after including Windows headers.
Acked-by: Johannes Schindelin <johannes.schindelin@gmx.de> Acked-by: Johannes Sixt <j6t@kdbg.org> Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Pat Thoyts <patthoyts@users.sourceforge.net>