fix make-sdist to omit too long filenames

Makefile

@@ -100,8 +100,6 @@ clean:
 	rm -rf tmp $(bins) $(mans) test configure  *.tix .hpc $(sources) \
 		doc/.ikiwiki html dist $(clibs)
 
-# Workaround for `cabal sdist` requiring all included files to be listed
-# in .cabal.
 sdist: clean $(mans)
 	./make-sdist.sh
 

make-sdist.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
+#
+# Workaround for `cabal sdist` requiring all included files to be listed
+# in .cabal.
 
 # Create target directory
 sdist_dir=git-annex-$(grep '^Version:' git-annex.cabal | sed -re 's/Version: *//')
@@ -6,8 +9,13 @@ mkdir --parents dist/$sdist_dir
 
 find . \( -name .git -or -name dist -or -name cabal-dev \) -prune \
 	-or -not -name \\*.orig -not -type d -print \
-| perl -ne 'print unless length >= 100' \
+| perl -ne "print unless length >= 100 - length q{$sdist_dir}" \
 | xargs cp --parents --target-directory dist/$sdist_dir
 
 cd dist
 tar -caf $sdist_dir.tar.gz $sdist_dir
+
+# Check that tarball can be unpacked by cabal.
+# It's picky about tar longlinks etc.
+rm -rf $sdist_dir
+cabal unpack $sdist_dir.tar.gz