Added option CMAKE_LIBRARY_SEARCH_PATH.

CMAKE_LIBRARY_SEARCH_PATH is to specify non-standard library
install locations. Can also be set as an environment variable.

CMakeLists.txt

@@ -24,6 +24,8 @@ SET (OGS_DATE "2012-08-20")
 ### Preliminary Options ###
 ###########################
 OPTION(OGS_NO_BOOST_DOWNLOAD "Always use the system installed Boost?" OFF)
+SET(CMAKE_LIBRARY_SEARCH_PATH "" CACHE PATH
+	"Additional library installation path, e.g. /opt/local or C:/libs")
 
 ### CMake includes ###
 INCLUDE(scripts/cmake/CheckTypeSizes.cmake)

scripts/cmake/Find.cmake

@@ -4,6 +4,14 @@ IF(APPLE)
 	LIST(APPEND CMAKE_LIBRARY_PATH $ENV{HOMEBREW_ROOT}/lib)
 ENDIF()
 
+# Add user-given library install paths, e.g. /opt/local
+LIST(APPEND CMAKE_INCLUDE_PATH
+	$ENV{CMAKE_LIBRARY_SEARCH_PATH}/include
+	${CMAKE_LIBRARY_SEARCH_PATH}/include)
+LIST(APPEND CMAKE_LIBRARY_PATH
+	$ENV{CMAKE_LIBRARY_SEARCH_PATH}/lib
+	${CMAKE_LIBRARY_SEARCH_PATH}/lib)
+
 ######################
 ### Find tools     ###
 ######################