This centralizes construction of the error message for an unclosed
logical block (if, foreach, etc.). We record the line at which each
block is opened so it can be reported in the error message.
When a function blocker decides to remove itself we previously removed
it at every return point from the C++ scope in which its removal is
needed. This teaches function blockers to transfer ownership of
themselves from cmMakefile to an automatic variable for deletion on
return. Since this removes blockers before they replay their commands,
we no longer need to avoid running blockers on their own commands.
Bill Hoffman
Brad King
Ken Martin
Amitha Perera