Add hghave utility and run-tests.py support. hghave detects system features like symlinks availability at run-time. Tests can be skipped by starting them with: "$TESTDIR/hghave" symlink || exit 80 The 80 exit status triggers hghave output handling by run-tests.py. Also, tests output can be locally patched on the fly to match reference output.

% init
% commit
adding base
% qnew mqbase
% qrefresh
% qdiff
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@ base
-base
+patched
% qdiff dirname
diff -r 67e992f2c4f3 base
--- a/base
+++ b/base
@@ -1,1 +1,1 @@ base
-base
+patched