cmake properly exclude llvm from the "all" target

-now we only build the parts of llvm that are actually required

CMakeLists.txt

@@ -45,13 +45,12 @@ add_custom_target(llvm_up DEPENDS llvm_gotorev clang_gotorev)
 # llvm
 set(LLVM_TARGETS_TO_BUILD "host" CACHE STRING "LLVM targets")
 #set(LLVM_EXTERNAL_CLANG_SOURCE_DIR "${CMAKE_SOURCE_DIR}/clang" CACHE String "Clang directory")
-#add_subdirectory(llvm EXCLUDE_FROM_ALL)
 if(ENABLE_INTEL_JIT_EVENTS)
   set(LLVM_USE_INTEL_JITEVENTS "ON" CACHE STRING "Enable building support for the Intel JIT Events API")
   set(INTEL_JIT_EVENTS_LIB "inteljitevents")
   add_definitions(-DENABLE_INTEL_JIT_EVENTS=1)
 endif()
-add_subdirectory(${DEPS_DIR}/llvm-trunk ${CMAKE_BINARY_DIR}/llvm)
+add_subdirectory(${DEPS_DIR}/llvm-trunk ${CMAKE_BINARY_DIR}/llvm EXCLUDE_FROM_ALL)
 set(CMAKE_MODULE_PATH "${CMAKE_BINARY_DIR}/llvm/share/llvm/cmake/")
 include(LLVMConfig)
 llvm_map_components_to_libnames(LLVM_LIBS core mcjit native bitreader ipo irreader debuginfo instrumentation ${INTEL_JIT_EVENTS_LIB})