build: Use a single po4a opt argument instead of the same per language

debian/changelog

@@ -94,6 +94,7 @@ dpkg (1.18.5) UNRELEASED; urgency=medium
     - Do not require passing the perl interpreter to run-script.
     - Quote dirname argument in run-script, to handle spaces in pathname.
       Reported by Carsten Hey <carsten@debian.org>.
+    - Use a single po4a opt argument instead of the same per language.
   * Packaging:
     - Enable all hardening flags, starting with gcc-5 there is no performance
       loss anymore when enabling PIE on i386.

man/po/po4a.cfg

@@ -2,18 +2,7 @@
 [po4a_paths] po/dpkg-man.pot $lang:po/$lang.po
 
 # Make sure the man pages are generated with the right encoding.
-[po4a_alias:man] man                           \
-                 opt_de:"-L UTF-8    -A UTF-8" \
-                 opt_es:"-L UTF-8    -A UTF-8" \
-                 opt_fr:"-L UTF-8    -A UTF-8" \
-                 opt_hu:"-L UTF-8    -A UTF-8" \
-                 opt_it:"-L UTF-8    -A UTF-8" \
-                 opt_ja:"-L UTF-8    -A UTF-8" \
-                 opt_pl:"-L UTF-8    -A UTF-8" \
-                 opt_pt_BR:"-L UTF-8 -A UTF-8" \
-                 opt_ru:"-L UTF-8    -A UTF-8" \
-                 opt_sv:"-L UTF-8    -A UTF-8" \
-                 opt_zh_CN:"-L UTF-8 -A UTF-8"
+[po4a_alias:man] man opt:"-L UTF-8 -A UTF-8"
 
 [type:man] deb.5 $lang:$lang/deb.5 \
            add_$lang:po/$lang.add