Find libusb-1.0 with pkg-config except on mingw, and fix #include path

configure.ac

@@ -343,16 +343,24 @@ if test "x$bitforce$modminer" != xnono; then
 fi
 AM_CONDITIONAL([HAVE_LIBUDEV], [test x$libudev != xno])
 
+PKG_PROG_PKG_CONFIG()
+
 if test "x$ztex" != xno; then
-  AC_CHECK_LIB(usb-1.0, libusb_init, ,
-          AC_MSG_ERROR([Could not find usb library - please install libusb]))
-  AC_DEFINE([HAVE_LIBUSB], [1], [Defined to 1 if libusb is wanted])
-  USB_LIBS="-lusb-1.0"
-  USB_FLAGS=""
+  case $target in
+    *-*-mingw*)
+      # workaround for libusbx windows binaries not including a .pc file
+      LIBUSB_LIBS="-LC:/MinGW/lib -lusb-1.0"
+      LIBUSB_CFLAGS="-IC:/MinGW/include/libusb-1.0"
+      AC_DEFINE(HAVE_LIBUSB, 1, [Define if you have libusb-1.0])
+      ;;
+    *)
+      PKG_CHECK_MODULES(LIBUSB, libusb-1.0, [AC_DEFINE(HAVE_LIBUSB, 1, [Define if you have libusb-1.0])], [AC_MSG_ERROR([Could not find usb library - please install libusb-1.0])])
+      ;;
+  esac
+  USB_LIBS="$LIBUSB_LIBS"
+  USB_FLAGS="$LIBUSB_CFLAGS"
 fi
 
-PKG_PROG_PKG_CONFIG()
-
 PKG_CHECK_MODULES([LIBCURL], [libcurl >= 7.18.2], ,[AC_MSG_ERROR([Missing required libcurl dev >= 7.18.2])])
 AC_SUBST(LIBCURL_LIBS)
 

libztex.h

@@ -22,7 +22,7 @@
 #ifndef __LIBZTEX_H__
 #define __LIBZTEX_H__
 
-#include <libusb-1.0/libusb.h>
+#include <libusb.h>
 
 #define LIBZTEX_MAX_DESCRIPTORS 512
 #define LIBZTEX_SNSTRING_LEN 10

miner.h

@@ -103,7 +103,7 @@ static inline int fsync (int fd)
 #endif
 
 #ifdef HAVE_LIBUSB
-  #include <libusb-1.0/libusb.h>
+  #include <libusb.h>
 #endif
 
 #ifdef USE_ZTEX