here docs in makefile

[Dan Jacobson]

In 5.1.1 Splitting Command Lines,  at

       Sometimes you want to split a long line inside of single quotes, but
    you don't want the backslash-newline to appear in the quoted content.
    This is often the case when passing scripts to languages such as Perl,
    where extraneous backslashes inside the script can change its meaning

mention 'using $(\
)is a great way to $(\
)do that that is even backward compatible with older make'

Also mention how one can do shell HERE docs please!

su proxy<<!
bla
bla
!

how to stuff that into a makefile?!

don't say "use su -c". OK, how about
wc<<!
bla
bla
!