gplugin/gplugin

add additional search directories to find libperl but make sure they're all absolute paths

make sure additional search directories to find libperl are absolute paths

Testing Done:
built on openSUSE, Debian Bullseye, and Ubuntu Hirsute

Reviewed at https://reviews.imfreedom.org/r/864/
syntax: glob
.*.swp
*.debhelper
*.orig
*.pyc
*.ui~
\#*.ui\#
syntax: regexp
^build.*\/
^packaging\/debian\/tmp\/
^packaging\/debian\/(.+\.)?(substvars|debhelper\.log)$
^packaging\/debian\/build.*\/
^packaging\/debian\/libgplugin0?(-.+)?\/
^packaging\/debian\/gir1.2-gplugin-0.0\/
^packaging\/debian\/files$
^po\/.*\.pot$
^obj-x86_64-linux-gnu\/
^debian\/?$