allow config file interpolation

test/boost_libs/cmake/autocmake.cfg

@@ -5,12 +5,9 @@ min_cmake_version: 2.8
 [cxx]
 source: ../../../modules/cxx.cmake
 
-[custom]
-source: custom/boost_version-components.cmake
-
 [boost]
+defaults: {'major': 1, 'minor': 59, 'patch': 0, 'components': 'chrono;timer;system'}
 source: ../../../modules/boost/boost.cmake
-fetch: http://sourceforge.net/projects/boost/files/boost/1.59.0/boost_1_59_0.zip
 
 [default_build_paths]
 source: ../../../modules/default_build_paths.cmake

test/boost_libs/cmake/custom/boost_version-components.cmake

@@ -1,2 +0,0 @@
-set(BOOST_MINIMUM_REQUIRED 1.59.0)
-list(APPEND BOOST_COMPONENTS_REQUIRED chrono timer system)

test/boost_libs/src/CMakeLists.txt

@@ -1,5 +1,13 @@
 add_executable(example example.cpp)
+
 if(BUILD_CUSTOM_BOOST)
     add_dependencies(example custom_boost)
 endif()
-target_link_libraries(example ${Boost_TIMER_LIBRARY} ${Boost_CHRONO_LIBRARY} ${Boost_SYSTEM_LIBRARY})
+
+set(_libs ${Boost_TIMER_LIBRARY} ${Boost_CHRONO_LIBRARY} ${Boost_SYSTEM_LIBRARY})
+
+if(NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+    set(_libs ${_libs} rt)
+endif()
+
+target_link_libraries(example ${_libs})