libusbemu: fix "expected unqualified-id before numeric constant" error

Undefine the error numeric constants before redefining them, some
systems define those in errno.h which can be brought in by some other
header.

platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp: In function ‘int ReapTransfer(transfer_wrapper*, unsigned int, libusbemu::QuickList<transfer_wrapper>*)’:
platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp:698: error: expected unqualified-id before numeric constant
platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp:704: error: ‘ETIMEOUT’ was not declared in this scope
platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp: At global scope:
platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp:745: error: expected unqualified-id before ‘return’
platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp:746: error: expected declaration before ‘}’ token

Signed-off-by: Antonio Ospite <[email protected]>

Author: Antonio Ospite

platform/windows/libusb10emu/libusb-1.0/libusbemu.cpp

@@ -695,6 +695,9 @@ int ReapTransfer(transfer_wrapper* wrapper, unsigned int timeout, libusb_device:
     // (a) the timeout passed to usb_reap_async_nocancel() expired;
     // (b) the transfer was cancelled via usb_cancel_async();
     // (c) some fatal error triggered.
+#undef EIO
+#undef EINVAL
+#undef ETIMEOUT
     enum EReapResult { EIO = -5, EINVAL = -22, ETIMEOUT = -116 };
     switch(read)
     {