build with libusb only on windows

Author: woodser

CMakeLists.txt

@@ -68,8 +68,10 @@ endif()
 # LibUSB
 ############
 
-find_library(usb_LIBRARY NAMES usb-1.0 libusb usb)
-set(LibUSB_LIBRARIES ${usb_LIBRARY})
+if (WIN32)
+  find_library(usb_LIBRARY NAMES usb-1.0 libusb usb)
+  list(APPEND EXTRA_LIBRARIES ${usb_LIBRARY})
+endif()
 
 ############
 # Boost
@@ -335,7 +337,6 @@ if (BUILD_LIBRARY)
       ${UNBOUND_LIBRARIES}
       ${Boost_LIBRARIES}
       ${Protobuf_LIBRARY}
-      ${LibUSB_LIBRARIES}
       ${OPENSSL_LIBRARIES}
       ${SODIUM_LIBRARY}
       ${HIDAPI_LIBRARIES}
@@ -428,7 +429,6 @@ if (BUILD_SAMPLE)
       ${UNBOUND_LIBRARIES}
       ${Boost_LIBRARIES}
       ${Protobuf_LIBRARY}
-      ${LibUSB_LIBRARIES}
       ${OPENSSL_LIBRARIES}
       ${SODIUM_LIBRARY}
       ${HIDAPI_LIBRARIES}
@@ -500,7 +500,6 @@ if (BUILD_SCRATCHPAD)
       ${UNBOUND_LIBRARIES}
       ${Boost_LIBRARIES}
       ${Protobuf_LIBRARY}
-      ${LibUSB_LIBRARIES}
       ${OPENSSL_LIBRARIES}
       ${SODIUM_LIBRARY}
       ${HIDAPI_LIBRARIES}
@@ -572,7 +571,6 @@ if (BUILD_TESTS)
       ${UNBOUND_LIBRARIES}
       ${Boost_LIBRARIES}
       ${Protobuf_LIBRARY}
-      ${LibUSB_LIBRARIES}
       ${OPENSSL_LIBRARIES}
       ${SODIUM_LIBRARY}
       ${HIDAPI_LIBRARIES}