elua: generate Makevars from Makevars.in with a dynamic conditional... sadly there doesn't seem to be any other way...

configure.ac

@@ -255,12 +255,14 @@ AM_GNU_GETTEXT_VERSION([0.17])
 m4_ifdef([AC_GNU_GETTEXT], [
 AC_GNU_GETTEXT([external])
 po_makefile_in=po/Makefile.in
+po_makevars=po/Makevars
 have_po="yes"
 ],
 [
 m4_ifdef([AM_GNU_GETTEXT], [
 AM_GNU_GETTEXT([external])
 po_makefile_in=po/Makefile.in
+po_makevars=po/Makevars
 have_po="yes"
 ],
 [
@@ -4474,6 +4476,7 @@ dbus-services/org.enlightenment.Ethumb.service
 systemd-services/efreet.service
 systemd-services/ethumb.service
 $po_makefile_in
+$po_makevars
 cmakeconfig/EinaConfig.cmake
 cmakeconfig/EinaConfigVersion.cmake:cmakeconfig/EFLConfigVersion.cmake.in
 cmakeconfig/EezeConfig.cmake