Created script that detects vcs info and writes it to a file.

vcstagger.py

@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+
+# Copyright 2015 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys, os, subprocess
+
+def tag(infile, outfile, fallback):
+    tagid = get_string(infile, fallback)
+    newdata = open(infile).read().replace('@VCS_TAG@', tagid)
+    try:
+        olddata = open(outfile).read()
+        if olddata == newdata:
+            return
+    except Exception:
+        pass
+    open(outfile, 'w').write(newdata)
+
+def get_string(infile, fallback):
+    absfile = os.path.join(os.getcwd(), infile)
+    directory = os.path.split(absfile)[0]
+    segs = directory.replace('\\', '/').split('/')
+    for i in range(len(segs), -1, -1):
+        curdir = '/'.join(segs[:i])
+        if os.path.isdir(os.path.join(curdir, '.git')):
+            output = subprocess.check_output(['git', 'describe'],
+                                             cwd = directory)
+            return output.decode().strip()
+        elif os.path.isdir(os.path.join(curdir, '.hg')):
+            output = subprocess.check_output(['hg', 'identify'],
+                                             cwd=directory)
+            return output.decode().strip()
+        elif os.path.isdir(os.path.join(curdir, '.bzr')):
+            output = subprocess.check_output(['bzr', 'revno'],
+                                             cwd=directory)
+            return output.decode().strip()
+        elif os.path.isdir(os.path.join(curdir, '.svn')):
+            output = subprocess.check_output(['svn', 'info'],
+                                             cwd=directory)
+            for line in output.decode().split('\n'):
+                (k, v) = line.split(':', 1)
+                if k.strip() == 'Revision':
+                    return v.strip()
+            raise RuntimeError('Svn output malformed.')
+    return fallback
+
+if __name__ == '__main__':
+    infile = sys.argv[1]
+    outfile = sys.argv[2]
+    fallback = sys.argv[3]
+    tag(infile, outfile, fallback)