[CMake] Add a pcl_find_libusb.cmake (#4653)

Author: larshg

CMakeLists.txt

@@ -313,7 +313,7 @@ endif()
 # libusb
 option(WITH_LIBUSB "Build USB RGBD-Camera drivers" TRUE)
 if(WITH_LIBUSB)
-  find_package(libusb)
+  include("${PCL_SOURCE_DIR}/cmake/pcl_find_libusb.cmake")
 endif()
 
 # Dependencies for different grabbers

cmake/Modules/Findlibusb.cmake

@@ -66,7 +66,7 @@ find_package_handle_standard_args(libusb DEFAULT_MSG libusb_LIBRARIES libusb_INC
 
 mark_as_advanced(libusb_INCLUDE_DIRS libusb_LIBRARIES)
 
-if(LIBUSB_FOUND)
+if(libusb_FOUND)
   add_library(libusb::libusb UNKNOWN IMPORTED)
   set_target_properties(libusb::libusb PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${libusb_INCLUDE_DIR}")
   set_target_properties(libusb::libusb PROPERTIES IMPORTED_LOCATION "${libusb_LIBRARIES}")

cmake/pcl_find_libusb.cmake

@@ -0,0 +1,34 @@
+#
+#pcl_find_libusb is used due to VCPKG making impossible to use local findXX modules.
+# and VCPKG findlibusb doesn't create the libusb targets.
+
+# Find and set libusb
+find_package(libusb)
+
+if(TARGET libusb::libusb)
+  #libusb target is found by the find_package script. 
+  #VCPKG skip PCLs findlibusb and sets its own variables which is handled below.
+  return()
+endif()
+
+#Handle VCPKG definitions
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(libusb DEFAULT_MSG LIBUSB_LIBRARIES LIBUSB_INCLUDE_DIRS)
+
+mark_as_advanced(LIBUSB_INCLUDE_DIRS LIBUSB_LIBRARIES)
+
+if(libusb_FOUND)
+  add_library(libusb::libusb UNKNOWN IMPORTED)
+  if(${LIBUSB_INCLUDE_DIRS})
+    set_target_properties(libusb::libusb PROPERTIES INTERFACE_INCLUDE_DIRECTORIES "${LIBUSB_INCLUDE_DIRS}")
+  endif()
+  if(EXISTS "${LIBUSB_LIBRARY}")
+    set_target_properties(libusb::libusb PROPERTIES IMPORTED_LOCATION ${LIBUSB_LIBRARY})
+  endif()
+  if(EXISTS "${LIBUSB_LIBRARY_DEBUG}")
+    set_target_properties(libusb::libusb PROPERTIES IMPORTED_LOCATION_DEBUG ${LIBUSB_LIBRARY_DEBUG})
+  endif()
+  if(EXISTS "${LIBUSB_LIBRARY_RELEASE}")
+    set_target_properties(libusb::libusb PROPERTIES IMPORTED_LOCATION_RELEASE ${LIBUSB_LIBRARY_RELEASE})
+  endif()
+endif()