如何为以下变量设置适合您的环境的值
在Makefile的顶部：
INSTALL_DIR the directory into which to install libraries,
executables and header files (e.g., /usr/local)
BOOST_INCL_DIR the parent directory of the boost/ header directory
(e.g., /usr/include)
BOOST_LIB_DIR the directory containing libboost_iostreams, etc.
BOOST_LIB linker flags for libboost_iostreams and libboost_system
BOOST_THREAD_LIB linker flags for libboost_thread