Frm ./configure:
    deplibs_check_method=`(./libtool --config; echo eval echo \$deplibs_check_me
thod) | sh`
    if test "X$deplibs_check_method" = Xnone; then
    echo "foo: $deplibs_check_method" >&AS_MESSAGE_LOG_FD
      use_indirect_deps=yes
    else
      use_indirect_deps=no
    fi

If libfoo links to libbar and use_indirect_deps is "no", -lbar is not automatically added along with -lfoo.

# Need to set the preceding variable on all platforms that support              
# interlibrary dependencies.                                                    
# 'none' -- dependencies not supported.                                         
# `unknown' -- same as none, but documents that we really don't know.           
# 'pass_all' -- all dependencies passed with no checks.                         
# 'test_compile' -- check by making test program.                               
# 'file_magic [[regex]]' -- check by looking for files in library path          
# which responds to the $file_magic_cmd with a given extended regex.            
# If you have `file' or equivalent on your system and you're not sure           
# whether `pass_all' will *always* work, you probably want this one.