tests: avoid test-hup hanging on AIX test-hup hangs on AIX. Under ksh89 on AIX (the default shell), echo Hello; while [ ! -s not-there ]; do true; done produces no output while the loop executes. Replacing 'true' with 'sleep 0' fixes, as does using a less broken shell. ksh93 is fine. Update check-code.py to look for this, and make same change in test-serve.t. In fact test-serve works fine, probably because of additional commands between echo and the loop, but that's a subtlety not easy to test for.

--- a/contrib/check-code.py	Thu Apr 05 15:39:07 2012 +0200
+++ b/contrib/check-code.py	Thu Apr 05 12:31:21 2012 +0100
@@ -94,6 +94,8 @@
      "explicit exit code checks unnecessary"),
     (uprefix + r'set -e', "don't use set -e"),
     (uprefixc + r'( *)\t', "don't use tabs to indent"),
+    (uprefixc + r'.*do\s*true;\s*done',
+     "don't use true as loop body, use sleep 0"),
   ],
   # warnings
   []