meson: Use @BASENAME@ more

This patch takes care of just the obvious cases: there are
many more situations where the data we pass to configure_file()
could likely be obtained in a more effective way, but we can
address the low-hanging fruits as a first approximation.

Signed-off-by: Andrea Bolognani <abologna@redhat.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>

po/meson.build

@@ -6,7 +6,7 @@ potfiles_conf.set('BUILDDIR', '')
 
 potfiles = configure_file(
   input: 'POTFILES.in',
-  output: 'POTFILES',
+  output: '@BASENAME@',
   configuration: potfiles_conf,
 )