configure.ac: consider libusb_os_handle absence non-fatal on Windows

Keep checking for the libusb_os_handle data type's presence, but don't
consider its absence on Windows fatal. Recent mainline libusb provides
something similar to the event abstraction branch under the common API.
Assume that it's the integrators' or packagers' responsibility to either
use a recent library or a patched older library for sigrok builds.

All other non-Windows platforms remain unaffected, the presence check
never was fatal there. The data type check itself needs to remain in
place because the usb.c source code adjusts to its presence.

diff --git a/configure.ac b/configure.ac
index 424b00022729e4ba70671bfdc17518c3b8646ed0..5c4808183b3625a8e453ecfec110453f13aa7429 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -630,9 +630,6 @@ AC_CHECK_FUNCS([ftdi_tciflush ftdi_tcoflush ftdi_tcioflush])
 LIBS=$sr_save_libs
 CFLAGS=$sr_save_cflags
 
-AM_COND_IF([NEED_USB], [AS_CASE([$sr_have_libusb_os_handle:$host_os], [no:mingw*],
-       [AC_MSG_ERROR([Windows builds require the event-abstraction branch of libusb])])])
-
 sr_glib_version=`$PKG_CONFIG --modversion glib-2.0 2>&AS_MESSAGE_LOG_FD`
 sr_libzip_version=`$PKG_CONFIG --modversion libzip 2>&AS_MESSAGE_LOG_FD`
 sr_zlib_version=`$PKG_CONFIG --modversion zlib 2>&AS_MESSAGE_LOG_FD`