Convert the check-for-missing files check to a python script

'git ls-files --exclude=<pattern>' was changed (intentionally!)
not to exclude anything files that are actually in the index.
Since git ls-files by default simply lists the files in the
index, this is a problem. Emulating this in shell went past
the limits of what made sense, so move it to a simple external
python script.

Makefile.am

@@ -6,7 +6,8 @@ SUBDIRS = data js src tests po man
 EXTRA_DIST =		\
 	.project	\
 	.settings	\
-	autogen.sh
+	autogen.sh	\
+	tools/check-for-missing.py
 
 # These are files checked into Git that we don't want to distribute
 DIST_EXCLUDE =					\
@@ -17,14 +18,4 @@ DIST_EXCLUDE =					\
 
 distcheck-hook:
 	@echo "Checking disted files against files in git"
-	@failed=false; \
+	@$(srcdir)/tools/check-for-missing.py $(srcdir) $(distdir) $(DIST_EXCLUDE)
-	exclude=`(for p in $(DIST_EXCLUDE) ; do echo --exclude=$$p ; done)`; \
-	for f in `cd $(srcdir) && git ls-files $$exclude` ; do \
-		if ! test -e $(distdir)/$$f ; then \
-			echo File missing from distribution: $$f ; \
-			failed=true ; \
-		fi \
-	done ; \
-	if $$failed ; then \
-		exit 1 ; \
-	fi

tools/check-for-missing.py

@@ -0,0 +1,25 @@
+#!/usr/bin/python
+#
+# This is a simple script that we use to check for files in git
+# and not in the distribution. It was previously written in shell
+# and inlined in the Makefile.am, but 'git ls-files --exclude=<pattern>'
+# was changed to no longer due anything useful, which made that
+# too challenging to be worthwhile.
+
+import fnmatch, os, subprocess, sys
+
+srcdir=sys.argv[1]
+distdir=sys.argv[2]
+excludes=sys.argv[3:]
+
+os.chdir(srcdir)
+
+status=0
+for f in subprocess.Popen(["git", "ls-files"], stdout=subprocess.PIPE).stdout:
+    f = f.strip()
+    if (not os.path.exists(os.path.join(distdir, f)) and
+        not any((fnmatch.fnmatch(f, p) for p in excludes))):
+        print "File missing from distribution:", f
+        status=1
+
+sys.exit(status)