Mac XCode program
1. Add additional header/libraries
For XCode project, add the "Header Search Paths" or "Library Search Paths" under "Search Paths" in xcodeproj.
2. Add additional link flags
For XCode project, for example, add "-lboost_system-xgcc42-1_51" and "-lboost_filesystem-xgcc42-1_51" under "Other Linker Flags".
dyld: Library not loaded: xxx.dylib
因为-rpath制定的搜索路径， 1, 是优先于LD_LIBRARY_PATH和/etc/ld.so.conf的；2, 它被写入到可执行文件中。
就因为第2条，所以无论可执行文件到那里，加载时都是到编译时用-rpath制定的路径去找
