Detect CMake warnings and errors in build output.

Fix niggly in ExternalProject that would inadvertently
create a log file of output when a command was explicitly
set to the empty string.

Also, increase the default value for showing context
around build errors to 10 lines, up from 6. Also add
the ability to customize this setting so that users
can put it back to 6 or even lower if they want, or
show more if they want.

0 files changed, 0 insertions, 0 deletions