build: Fix "update-translations" target for builddir != srcdir

More of a crummy work-around, but it usually only runs on my system, so
it shouldn't be a big bother.

Makefile.am

@@ -80,6 +80,7 @@ all: $(defaultmakedeps)
 
 create-pot:
 	$(AM_V_GEN) $(MAKE) -C po shared-mime-info.pot
+	cp -a po/shared-mime-info.pot $(top_srcdir)/po/
 
 XDGMIME_PATH=@XDGMIME_PATH@
 
@@ -145,8 +146,8 @@ check-translations:
 	if [ $$RET == 1 ] ; then exit 1; fi
 
 update-translations: create-pot
-	@tx pull --all --force --skip
-	@tx push --source
+	@tx pull --all --force --skip --root $(top_srcdir)
+	@tx push --source --root $(top_srcdir)
 
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