Windows: Fix poll implementation for NDEBUG (Release) builds

The refactoring in commit df61c0c3a3 ("Windows: improve poll
abstraction") introduced a bug in builds where NDEBUG is defined because
of a statement with side-effects that was put inside an assertion. When
this statement is not evaluated, the file descriptor table gets corrupt.
Fix this by moving the statement outside of the assertion.

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>

libusb/os/poll_windows.c

diff --git a/libusb/os/poll_windows.c b/libusb/os/poll_windows.c
index 830c7e5..f735245 100644
--- a/libusb/os/poll_windows.c
+++ b/libusb/os/poll_windows.c
@@ -135,12 +135,14 @@
 	for (n = 0; n < fd_table_size; n += BITMAP_BITS_PER_WORD) {
 		unsigned int idx = n / BITMAP_BITS_PER_WORD;
 		ULONG mask, pos = 0U;
+		unsigned char nonzero;
 
 		mask = ~fd_table_bitmap[idx];
 		if (mask == 0U)
 			continue;
 
-		assert(_BitScanForward(&pos, mask));
+		nonzero = _BitScanForward(&pos, mask);
+		assert(nonzero);
 		fd_table_bitmap[idx] |= 1U << pos;
 		n += pos;
 		break;

libusb/version_nano.h

diff --git a/libusb/version_nano.h b/libusb/version_nano.h
index 18c8cb7..7e27bf5 100644
--- a/libusb/version_nano.h
+++ b/libusb/version_nano.h
@@ -1 +1 @@
-#define LIBUSB_NANO 11452
+#define LIBUSB_NANO 11453