hyperion.ng/cmake/FindUDev.cmake

# razor-de: Configure libudev environment
#
# UDEV_FOUND - system has a libudev
# UDEV_INCLUDE_DIR - where to find header files
# UDEV_LIBRARIES - the libraries to link against udev
# UDEV_STABLE - it's true when is the version greater or equals to 143 - version when the libudev was stabilized in its API
#
# copyright (c) 2011 Petr Vanek <petr@scribus.info>
# Redistribution and use is allowed according to the terms of the BSD license.
#

FIND_PATH(
	UDEV_INCLUDE_DIR
	libudev.h
	/usr/include
	/usr/local/include
	${UDEV_PATH_INCLUDES}
)

FIND_LIBRARY(
	UDEV_LIBRARIES
	NAMES udev libudev
	PATHS
		/usr/lib${LIB_SUFFIX}
		/usr/local/lib${LIB_SUFFIX}
		${UDEV_PATH_LIB}
)

IF (UDEV_LIBRARIES AND UDEV_INCLUDE_DIR)
	SET(UDEV_FOUND "YES")
	execute_process(COMMAND pkg-config --atleast-version=143 libudev RESULT_VARIABLE UDEV_STABLE)
	# retvale is 0 of the condition is "true" so we need to negate the value...
	if (UDEV_STABLE)
		set(UDEV_STABLE 0)
	else ()
		set(UDEV_STABLE 1)
	endif ()
	message(STATUS "libudev stable: ${UDEV_STABLE}")
ENDIF ()

IF (UDEV_FOUND)
	MESSAGE(STATUS "Found UDev: ${UDEV_LIBRARIES}")
	MESSAGE(STATUS "   include: ${UDEV_INCLUDE_DIR}")
ELSE ()
	MESSAGE(STATUS "UDev not found.")
	MESSAGE(STATUS "UDev: You can specify includes: -DUDEV_PATH_INCLUDES=/opt/udev/include")
	MESSAGE(STATUS "      currently found includes: ${UDEV_INCLUDE_DIR}")
	MESSAGE(STATUS "UDev: You can specify libs: -DUDEV_PATH_LIB=/opt/udev/lib")
	MESSAGE(STATUS "      currently found libs: ${UDEV_LIBRARIES}")
	IF (UDev_FIND_REQUIRED)
		MESSAGE(FATAL_ERROR "Could not find UDev library")
	ENDIF ()
ENDIF ()