Fix compile errors in previous commit.
Brown-paper-bag bug... the previous commit didn't even compile.
This is the code I meant to write; I've tested that this version
works, but I haven't put hours on it to see if it fixes the sporadic bug
I was trying to fix.
Detect compile errors more robustly
In my environment:

java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) 64-Bit Server VM (build 20.1-b02, mixed mode)
(Sun Java 6 JDK 6.26, running under Debian Linux)

the compile output from a compiler error does not include the string
"error:" that build.xml looked for; so build.xml continues past compile
errors and apparently succeeds, unless you scroll back and specifically
look for error messages.  Fix build.xml to look for "error" instead of
"errors:".