windows: Silence zero-sized array warning in libusb.h for msvc

Silence "nonstandard extension used : zero-sized array in struct/union"
(C4200) warning caused by use of ZERO_SIZED_ARRAY in structures defined
in libusb.h when compiling with msvc.

A libusb user including the header from a c++ file is more likely to be
annoyed by the warning because it is activated at level 2 as opposed to
being included from a C file, where it's not activated until level 4.
(on msvc, level 4 is the last step before -Wall).

This causes problems when you also enable -Werror for your own source,
since the libusb header just gets merged into the compilation unit.

9>C:\src\libusb\libusb\libusb.h(786,11): error C2220: the following warning is treated as an error
9>C:\src\libusb\libusb\libusb.h(786,11): error C2220: 	uint8_t  dev_capability_data[ZERO_SIZED_ARRAY];
9>C:\src\libusb\libusb\libusb.h(786,11): error C2220: 	         ^
9>C:\src\libusb\libusb\libusb.h(786,11): warning C4200: nonstandard extension used: zero-sized array in struct/union
9>C:\src\libusb\libusb\libusb.h(786,11): warning C4200: 	uint8_t  dev_capability_data[ZERO_SIZED_ARRAY];
9>C:\src\libusb\libusb\libusb.h(786,11): warning C4200: 	         ^
9>C:\src\libusb\libusb\libusb.h(811,47): warning C4200: nonstandard extension used: zero-sized array in struct/union
5>C:\src\libusb\libusb\libusb.h(811,47): warning C4200: 	struct libusb_bos_dev_capability_descriptor *dev_capability[ZERO_SIZED_ARRAY];
5>C:\src\libusb\libusb\libusb.h(811,47): warning C4200: 	                                             ^
9>C:\src\libusb\libusb\libusb.h(1284,38): warning C4200: nonstandard extension used: zero-sized array in struct/union
9>C:\src\libusb\libusb\libusb.h(1284,38): warning C4200: 	struct libusb_iso_packet_descriptor iso_packet_desc[ZERO_SIZED_ARRAY];
9>C:\src\libusb\libusb\libusb.h(1284,38): warning C4200: 	                                    ^
9>Done building project "hotplugtest.vcxproj" -- FAILED.

Closes #1112
diff --git a/libusb/libusb.h b/libusb/libusb.h
index 61cacc9..2592ea7 100644
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -26,6 +26,9 @@
 #define LIBUSB_H
 #if defined(_MSC_VER)
+#pragma warning(push)
+/* Disable: warning C4200: nonstandard extension used : zero-sized array in struct/union */
+#pragma warning(disable:4200)
 /* on MS environments, the inline keyword is available in C++ only */
 #if !defined(__cplusplus)
 #define inline __inline
@@ -2128,6 +2131,10 @@
 int LIBUSB_CALL libusb_set_option(libusb_context *ctx, enum libusb_option option, ...);
+#ifdef _MSC_VER
+#pragma warning(pop)
 #if defined(__cplusplus)