build-aux: rewrite po file minimizer in Python

As part of an goal to eliminate Perl from libvirt build tools,
rewrite the minimize-po.pl tool in Python.

This was a straight conversion, manually going line-by-line to
change the syntax from Perl to Python. Thus the overall structure
of the file and approach is the same.

Reviewed-by: Ján Tomko <jtomko@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

scripts/minimize-po.py

@@ -0,0 +1,56 @@
+#!/usr/bin/env python
+#
+# Copyright (C) 2018-2019 Red Hat, Inc.
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library.  If not, see
+# <http://www.gnu.org/licenses/>.
+
+from __future__ import print_function
+
+import re
+import sys
+
+block = []
+msgstr = False
+empty = False
+unused = False
+fuzzy = False
+
+for line in sys.stdin:
+    if line.isspace():
+        if not empty and not unused and not fuzzy:
+            for b in block:
+                print(b, end='')
+
+        block = []
+        msgstr = False
+        fuzzy = False
+        block.append(line)
+    else:
+        if line.startswith("msgstr"):
+            msgstr = True
+            empty = True
+
+        if line[0] == '#' and "fuzzy" in line:
+            fuzzy = True
+        if line.startswith("#~ msgstr"):
+            unused = True
+        if msgstr and re.search(r'".+"', line):
+            empty = False
+
+        block.append(line)
+
+if not empty and not unused and not fuzzy:
+    for b in block:
+        print(b, end='')