Remove lambda.h from lang/scala.c

I'm a bit worried that everything is going to fall apart when it comes
to attempting to do "context.c", but for now I'll have to live with it
-- it's bedtime!

All that's left to convert are:

 * context.c
 * lang/c.c

which are, unfortunately, the two most difficult...
Only find a single JAR

It turns out that I was improperly searching for JAR files in a manner
that could return more than one.  This fix ensures that I only find a
single JAR file per -l flag.