def mac_set_relative_dylib_deps(libname):
    """
    On Mac OS X set relative paths to dynamic library dependencies of `libname`.

    Relative paths allow to avoid using environment variable DYLD_LIBRARY_PATH.
    There are known some issues with DYLD_LIBRARY_PATH. Relative paths is
    more flexible mechanism.

    Current location of dependend libraries is derived from the location
    of the executable (paths start with '@executable_path').

    @executable_path or @loader_path fail in some situations
    (@loader_path - qt4 plugins, @executable_path -
    Python built-in hashlib module).
    """

    from PyInstaller.lib.macholib import util
    from PyInstaller.lib.macholib.MachO import MachO

    # Ignore bootloader otherwise PyInstaller fails with exception like
    # 'ValueError: total_size > low_offset (288 > 0)'
    if os.path.basename(libname) in _BOOTLOADER_FNAMES:
        return

    def match_func(pth):
        """For system libraries is still used absolute path. It is unchanged."""
        # Match non system dynamic libraries.
        if not util.in_system_path(pth):
            # Use relative path to dependend dynamic libraries bases on
            # location of the executable.
            return os.path.join('@executable_path', os.path.basename(pth))

    # Rewrite mach headers with @executable_path.
    dll = MachO(libname)
    dll.rewriteLoadCommands(match_func)

    # Write changes into file.
    # Write code is based on macholib example.
    try:
        f = open(dll.filename, 'rb+')
        for header in dll.headers:
            f.seek(0)
            dll.write(f)
        f.seek(0, 2)
        f.flush()
        f.close()
    except Exception:
        pass
On Mac OS X set relative paths to dynamic library dependencies of `libname`.

    Relative paths allow to avoid using environment variable DYLD_LIBRARY_PATH.
    There are known some issues with DYLD_LIBRARY_PATH. Relative paths is
    more flexible mechanism.

    Current location of dependend libraries is derived from the location
    of the executable (paths start with '@executable_path').

    @executable_path or @loader_path fail in some situations
    (@loader_path - qt4 plugins, @executable_path -
    Python built-in hashlib module).