add support for libusb-win32

It is API compatible with libusb-0.1 that is already supported
but uses different header file name to prevent conflict with
Window's own usb.h.

ChangeLog

@@ -1,3 +1,12 @@
+2011-12-27 Chris Bagwell <chris at cnpbagwell dot com>
+	* configure.in, configure, config.h.in, sanei_usb.c,
+	check-usb-chip.c, sane-find-scanner.c: Add check for
+	libusb-win32 which is API compatible with libusb-0.1
+	but has different header file name to prevent conflicts
+	with Windows own usb.h.  Since libusb-1.0 is scheduled to
+	support Windows (not a forked version), it will probably
+	work as-is if user has pkg-config installed under mingw.
+
 2011-12-20 m. allan noah <kitno455 at gmail dot com>
 	* backend/fujitsu*, doc/descriptions/fujitsu.desc: backend v109
 	- added some MS and INQ information

configure

@@ -9753,6 +9753,58 @@ fi
 fi
 
 
+    for ac_header in lusb0_usb.h
+do :
+  ac_fn_c_check_header_mongrel "$LINENO" "lusb0_usb.h" "ac_cv_header_lusb0_usb_h" "$ac_includes_default"
+if test "x$ac_cv_header_lusb0_usb_h" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LUSB0_USB_H 1
+_ACEOF
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for usb_interrupt_read in -lusb" >&5
+$as_echo_n "checking for usb_interrupt_read in -lusb... " >&6; }
+if ${ac_cv_lib_usb_usb_interrupt_read+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lusb  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char usb_interrupt_read ();
+int
+main ()
+{
+return usb_interrupt_read ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_usb_usb_interrupt_read=yes
+else
+  ac_cv_lib_usb_usb_interrupt_read=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_usb_usb_interrupt_read" >&5
+$as_echo "$ac_cv_lib_usb_usb_interrupt_read" >&6; }
+if test "x$ac_cv_lib_usb_usb_interrupt_read" = xyes; then :
+  USB_LIBS="$USB_LIBS -lusb"
+				   HAVE_USB=yes
+fi
+
+fi
+
+done
+
   fi
   ;;
   esac

configure.in

@@ -371,9 +371,13 @@ if test "$enable_libusb" != "no"; then
     dnl Fallback to the old libusb
     dnl libusb >= 0.1.8 is required, as we need usb_interrupt_read()
     AC_CHECK_HEADER(usb.h,
-                    AC_CHECK_LIB(usb, usb_interrupt_read, 
+                    AC_CHECK_LIB(usb, usb_interrupt_read,
                                  [USB_LIBS="$USB_LIBS -lusb"
                                   HAVE_USB=yes]))
+    AC_CHECK_HEADERS(lusb0_usb.h,
+		     AC_CHECK_LIB(usb, usb_interrupt_read,
+				  [USB_LIBS="$USB_LIBS -lusb"
+				   HAVE_USB=yes]))
   fi
   ;;
   esac

include/sane/config.h.in

@@ -186,6 +186,9 @@
 /* Define if the long long type is available. */
 #undef HAVE_LONG_LONG
 
+/* Define to 1 if you have the <lusb0_usb.h> header file. */
+#undef HAVE_LUSB0_USB_H
+
 /* Define to 1 if you have the <machine/cpufunc.h> header file. */
 #undef HAVE_MACHINE_CPUFUNC_H
 

sanei/sanei_usb.c

@@ -67,7 +67,11 @@
 #endif
 
 #ifdef HAVE_LIBUSB
+#ifdef HAVE_LUSB0_USB_H
+#include <lusb0_usb.h>
+#else
 #include <usb.h>
+#endif
 #endif /* HAVE_LIBUSB */
 
 #ifdef HAVE_LIBUSB_1_0

tools/check-usb-chip.c

@@ -35,7 +35,11 @@
 #include <string.h>
 #include <errno.h>
 
+#ifdef HAVE_LUSB0_USB_H
+#include <lusb0_usb.h>
+#else
 #include <usb.h>
+#endif
 
 #include "../include/_stdint.h"
 

tools/sane-find-scanner.c

@@ -42,7 +42,11 @@
 #include "../include/sane/sanei_config.h"
 
 #ifdef HAVE_LIBUSB
+#ifdef HAVE_LUSB0_USB_H
+#include <lusb0_usb.h>
+#else
 #include <usb.h>
+#endif
 extern char * check_usb_chip (struct usb_device *dev, int verbosity, SANE_Bool from_file);
 #endif