Set path to perl binary.

gsed -i 's;/usr/bin/perl;/usr/pkg/bin/perl;' \
    ikiwiki-calendar.in ikiwiki-mass-rebuild \
    ikiwiki-transition.in ikiwiki-update-wikilist \
    ikiwiki-w3m.cgi ikiwiki.in gitremotes mdwn2man pm_filter \
    *.pm IkiWiki/*.pm IkiWiki/*/*.pm* *.setup */*.setup */*/*.setup \
    po/po2wiki t/*.t \
    plugins/externaldemo

Add NetBSD git to PATH.

gsed -i 's,^\$ENV{PATH}="\([^"]*\)";,$ENV{PATH}="/usr/pkg/bin:\1";,' ikiwiki.in

NetBSD sed doesn't recognize -i; use GNU sed instead.

gsed -i -e '/sed.*-i/s/\<sed\>/gsed/g' Makefile.PL

Build and install.

perl Makefile.PL INSTALL_BASE=$HOME/local PREFIX= MAKE=gmake
gmake
gmake install