Improve diagnostics. Previously, targets reference A/B/C//D where the A/B/C

part was incorrect, generated an internal error and backtrace. Now it's
property reported as invalid target id.


[SVN r23134]

tools/build

@@ -1 +1 @@
-Subproject commit ba6858dbd132d543b65b758dae5c2eca1fadfc0e
+Subproject commit be0850053839ce897589a9a45c4f2b6ecb45c0ce