executables in binary package, not rebuilt during build

root@gutsy:~# apt-get source dict-af
Reading package lists... Done
Building dependency tree
Reading state information... Done
Need to get 1164kB of source archives.
Get:1 http://archive.ubuntu.com gutsy/main dict-af 20070203-1 (dsc) [672B]
Get:2 http://archive.ubuntu.com gutsy/main dict-af 20070203-1 (tar) [1161kB]
Get:3 http://archive.ubuntu.com gutsy/main dict-af 20070203-1 (diff) [2033B]
Fetched 1164kB in 0s (19.2MB/s)
gpg: Signature made Tue Feb 6 23:00:39 2007 UTC using DSA key ID 0F932C9C
gpg: Can't check signature: public key not found
dpkg-source: extracting dict-af in dict-af-20070203
dpkg-source: unpacking dict-af_20070203.orig.tar.gz
dpkg-source: applying ./dict-af_20070203-1.diff.gz
root@gutsy:~# cd dict-af-20070203/
root@gutsy:~/dict-af-20070203# ls -al utils/munch; file utils/munch
-rwxr-xr-x 1 root root 19376 Feb 6 2007 utils/munch
utils/munch: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.4.1, dynamically linked (uses shared libs), not stripped
root@gutsy:~/dict-af-20070203# debian/rules clean
dh_testdir
dh_testroot
rm -f build-stamp
/usr/bin/make -C af clean
make[1]: Entering directory `/root/dict-af-20070203/af'
rm -f myspell/wordlist.iso-8859-1 myspell/pack-af-ZA-20060117.zip myspell/af_ZA.zip myspell/af_ZA.dic myspell/spell.txt myspell/VERSION_af_ZA.txt myspell/install.js myspell/spell-af-ZA.xpi myspell/af-ZA.dic myspell/af-ZA.aff myspell/README-af-ZA.txt
rm -f ispell/afrikaans.hash ispell/afrikaans-ispell-20060117.tar.bz2 ispell/wordlist.iso-8859-1 ispell/wordlist.iso-8859-1.cnt ispell/wordlist.iso-8859-1.stat
rm -rf aspell/wordlist.iso-8859-1 aspell/af.rws aspell/aspell-af-0.50-20060117.tar.bz2 aspell/proc aspell/configure aspell/af.cwl aspell/info aspell/Makefile aspell/Makefile.pre aspell/af.* aspell/*.alias aspell/COPYING aspell/README aspell/aspell-af-0.50-20060117
rm -rf wordlists/wordlist.iso-8859-1 wordlists/wordlist.aksente.iso-8859-1 wordlists/wordlist.birds.iso-8859-1 wordlists/wordlist.carriculum-2005.iso-8859-1 wordlists/wordlist.fish.iso-8859-1 wordlists/wordlist.internet.AWS.iso-8859-1 wordlists/wordlist.internet.iso-8859-1 wordlists/wordlist.internetterms.iso-8859-1 wordlists/wordlist.motorterms.iso-8859-1 wordlists/wordlist.nieuwoudt.iso-8859-1 wordlists/wordlist.otherwords.iso-8859-1 wordlists/wordlist.postcodes.iso-8859-1 wordlists/wordlist.viljoen.iso-8859-1 wordlists/wordlist.wineterms.iso-8859-1 wordlists/wordlist.wolff.iso-8859-1
rm -rf acor/acor_af-ZA.dat*
make[1]: Leaving directory `/root/dict-af-20070203/af'
rm -f af/myspell/*.zip af/myspell/*.xpi
rm -f af/wordlists/*.zip
dh_clean
root@gutsy:~/dict-af-20070203# ls -al utils/munch; file utils/munch
-rwxr-xr-x 1 root root 19376 Feb 6 2007 utils/munch
utils/munch: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.4.1, dynamically linked (uses shared libs), not stripped
root@gutsy:~/dict-af-20070203# debian/rules build
/usr/bin/make -C af myspell aspell
make[1]: Entering directory `/root/dict-af-20070203/af'
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.aksente.in >wordlists/wordlist.aksente.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.birds.in >wordlists/wordlist.birds.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.carriculum-2005.in >wordlists/wordlist.carriculum-2005.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.fish.in >wordlists/wordlist.fish.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.internet.AWS.in >wordlists/wordlist.internet.AWS.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.internet.in >wordlists/wordlist.internet.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.internetterms.in >wordlists/wordlist.internetterms.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.motorterms.in >wordlists/wordlist.motorterms.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.nieuwoudt.in >wordlists/wordlist.nieuwoudt.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.otherwords.in >wordlists/wordlist.otherwords.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.postcodes.in >wordlists/wordlist.postcodes.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.viljoen.in >wordlists/wordlist.viljoen.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.wineterms.in >wordlists/wordlist.wineterms.iso-8859-1
iconv -f utf-8 -t iso-8859-1 < wordlists/wordlist.wolff.in >wordlists/wordlist.wolff.iso-8859-1
cat wordlists/wordlist.aksente.iso-8859-1 wordlists/wordlist.birds.iso-8859-1 wordlists/wordlist.carriculum-2005.iso-8859-1 wordlists/wordlist.fish.iso-8859-1 wordlists/wordlist.internet.AWS.iso-8859-1 wordlists/wordlist.internet.iso-8859-1 wordlists/wordlist.internetterms.iso-8859-1 wordlists/wordlist.motorterms.iso-8859-1 wordlists/wordlist.nieuwoudt.iso-8859-1 wordlists/wordlist.otherwords.iso-8859-1 wordlists/wordlist.postcodes.iso-8859-1 wordlists/wordlist.viljoen.iso-8859-1 wordlists/wordlist.wineterms.iso-8859-1 wordlists/wordlist.wolff.iso-8859-1 | egrep -v "^#|^$" | sort --unique > wordlists/wordlist.iso-8859-1
egrep -v '(^#| )' <wordlists/wordlist.iso-8859-1 >myspell/wordlist.iso-8859-1
../utils/munch myspell/wordlist.iso-8859-1 myspell/af_ZA.aff >myspell/af_ZA.dic
/bin/sh: ../utils/munch: not found
make[1]: *** [myspell/af_ZA.dic] Error 127
make[1]: Leaving directory `/root/dict-af-20070203/af'
make: *** [build-stamp] Error 2
root@gutsy:~/dict-af-20070203# ls -al utils/munch; file utils/munch
-rwxr-xr-x 1 root root 19376 Feb 6 2007 utils/munch
utils/munch: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), for GNU/Linux 2.4.1, dynamically linked (uses shared libs), not stripped
root@gutsy:~/dict-af-20070203#