git-svn: allow disabling expensive broken symlink checks

Since dbc6c74d0858d77e61e092a48d467e725211f8e9, git-svn has had
an expensive check for broken symlinks that exist in some
repositories.  This leads to a heavy performance hit on
repositories with many empty blobs that are not supposed to be
symlinks.

The workaround is enabled by default; and may be disabled via:

  git config svn.brokenSymlinkWorkaround false

Reported by Markus Heidelberg.

Signed-off-by: Eric Wong <normalperson@yhbt.net>
diff --git a/t/t9131-git-svn-empty-symlink.sh b/t/t9131-git-svn-empty-symlink.sh
index 704a4f8..20529a8 100755
--- a/t/t9131-git-svn-empty-symlink.sh
+++ b/t/t9131-git-svn-empty-symlink.sh
@@ -87,4 +87,14 @@
 test_expect_success 'get "bar" => symlink fix from svn' \
 		'(cd x && git svn rebase)'
 test_expect_success '"bar" becomes a symlink' 'test -L x/bar'
+
+
+test_expect_success 'clone using git svn' 'git svn clone -r1 "$svnrepo" y'
+test_expect_success 'disable broken symlink workaround' \
+  '(cd y && git config svn.brokenSymlinkWorkaround false)'
+test_expect_success '"bar" is an empty file' 'test -f y/bar && ! test -s y/bar'
+test_expect_success 'get "bar" => symlink fix from svn' \
+		'(cd y && git svn rebase)'
+test_expect_success '"bar" does not become a symlink' '! test -L y/bar'
+
 test_done