- Now fails with the message

  Makefile:6: recipe for target 'refman.pdf' failed 
  gmake[4]: *** [refman.pdf] Error 1

- If you look at refman.log at WRKOBJDIR, you will find
  following message.
    -----------------------
    ) (./util_2twi_8h.tex [334]) (./wdt_8h.tex)
    ! Undefined control sequence.
    l.303 \backmatter
    -----------------------                 
  But if you invoke pdflatex there, it will finish successfully.
     ------------------------
    h87@makoto 11:24:16/150206(..wip/avr-libc)% \
    (cd /export/WRKOBJDIR/wip/avr-libc/work/avr-libc-1.8.1/doc/api/latex_src; \
    pdflatex refman.tex)
    
    This is pdfTeX, Version 3.1415926-2.5-1.40.14 (Web2C 2013)
     restricted \write18 enabled.
    entering extended mode
    (./refman.tex
    LaTeX2e <2011/06/27>
    Babel <v3.8l> and hyphenation patterns for english, dumylang, nohyphenation, ba
    sque, bulgarian, catalan, croatian, czech, danish, dutch, esperanto, estonian, 
    finnish, french, german, ngerman, monogreek, greek, hungarian, icelandic, indon
    esian, irish, italian, latin, bokmal, nynorsk, polish, portuguese, romanian, ru
    ssian, serbian, slovak, slovenian, spanish, swedish, turkish, ukrainian, loaded
    .
    
    
    h87@makoto 11:24:50/150206(..wip/avr-libc)% \
    (cd /export/WRKOBJDIR/wip/avr-libc/work/avr-libc-1.8.1/doc/api/latex_src; \
    ls -la refman.*)
    
    -rw-r--r--  1 makoto  wheel   151259 Feb  6 11:24 refman.aux
    -rw-r--r--  1 makoto  wheel   224993 Feb  6 11:24 refman.idx
    -rw-r--r--  1 makoto  wheel   245014 Feb  6 11:24 refman.log
    -rw-r--r--  1 makoto  wheel    81192 Feb  6 11:24 refman.out
    -rw-r--r--  1 makoto  wheel  1595768 Feb  6 11:24 refman.pdf
    -rw-r--r--  1 makoto  wheel     7415 Feb  5 10:05 refman.tex
    -rw-r--r--  1 makoto  wheel   539317 Feb  6 11:24 refman.toc
    h87@makoto 11:25:05/150206(..wip/avr-libc)% 
    ------------------------
