Find Boost also in C:/libs/boost.

scripts/cmake/ExternalProjectBoost.cmake

@@ -55,7 +55,8 @@ IF(NOT Boost_INCLUDE_DIRS)
 	IF(WIN32)
 		SET(Boost_USE_STATIC_LIBS ON)
 		IF(NOT DEFINED BOOST_LIBRARYDIR)
-			SET(BOOST_LIBRARYDIR "C:/boost/lib${BITS}-${BOOST_TOOLSET};$ENV{BOOST_ROOT}/lib${BITS}-${BOOST_TOOLSET}")
+			SET(BOOST_LIBRARYDIR "$ENV{CMAKE_LIBRARY_SEARCH_PATH}/boost/lib${BITS}-${BOOST_TOOLSET};C:/boost/lib${BITS}-${BOOST_TOOLSET};$ENV{BOOST_ROOT}/lib${BITS}-${BOOST_TOOLSET}")
+			SET(BOOST_INCLUDEDIR "$ENV{CMAKE_LIBRARY_SEARCH_PATH}/boost;C:/boost;$ENV{BOOST_ROOT}")
 		ENDIF()
 	ENDIF()
 	FIND_PACKAGE(Boost 1.46.0 COMPONENTS ${BOOST_LIBS_TO_BUILD})