build: Bump po4a version

We are using --porefs wrap option which was introduced in 0.43.

README

@@ -98,7 +98,7 @@ will be needed:
 
 To enable translated documentation this software will be needed:
 
-  po4a >= 0.36.4 (>= 0.41 for VPATH builds)
+  po4a >= 0.43
 
 To enable code coverage («./configure --enable-coverage; make coverage»)
 this software is needed:

debian/changelog

@@ -15,6 +15,7 @@ dpkg (1.18.11) UNRELEASED; urgency=medium
     - Check the availability of -W<warning> variant instead of -Wno-<warning>.
       As at least gcc and clang do not warn on -Wno-* warning flags, only
       when some unrelated warning needs to be emitted.
+    - Bump po4a version to 0.43 (we are using --porefs wrap option).
 
   [ Updated manpages translations ]
   * German (Helge Kreutzmann).

debian/control

@@ -11,7 +11,9 @@ Vcs-Git: https://anonscm.debian.org/git/dpkg/dpkg.git
 Standards-Version: 3.9.8
 Build-Depends: dpkg-dev (>= 1.17.14), debhelper (>= 9.20141010),
  pkg-config,
- gettext (>= 0.19), po4a (>= 0.41),
+ gettext (>= 0.19),
+# Needed for --porefs.
+ po4a (>= 0.43),
  zlib1g-dev, libbz2-dev, liblzma-dev,
  libselinux1-dev (>= 1.28-4) [linux-any],
  libncursesw5-dev,