fixes #238 improve Debug linking time by building LLVM -O3

-this significantly reduces the size of the resulting object files

CMakeLists.txt

@@ -32,7 +32,7 @@ endif()
 
 # llvm disable debug info unless ENABLE_LLVM_DEBUG is ON
 if(${CMAKE_BUILD_TYPE} STREQUAL "Debug" AND NOT ENABLE_LLVM_DEBUG)
-  set(CMAKE_CXX_FLAGS_DEBUG "-g0" CACHE STRING "" FORCE)
+  set(CMAKE_CXX_FLAGS_DEBUG "-O3" CACHE STRING "" FORCE)
 endif()
 
 execute_process(COMMAND cat llvm_revision.txt WORKING_DIRECTORY ${CMAKE_SOURCE_DIR} OUTPUT_VARIABLE LLVMREV OUTPUT_STRIP_TRAILING_WHITESPACE)