[CMake] graceful INSTALL failure

[Brandon J. Van Every]

This may seem like a nitpicky request, but I think there's an end-user 
usability issue.  I would like INSTALL to fail gracefully if some part 
of the build doesn't get generated.  Like, I have the option to do a 
partial INSTALL if I so choose.  I don't want to predetermine whether 
all of my installation dependencies will be fulfilled.  Currently, if 
any installation component fails, it stops the whole installation in its 
tracks.  Now under a Make system perhaps 'make -k' is sufficient to get 
past this.  But on VC++ it just dies, and I couldn't tell you how to 
keep going.

Users often haven't ensured that tools like MAKEINFO are properly 
installed.  Now of course, I can conditionally generate my build 
targets, tell them to install the tool, and tell them to re-run CMake.  
But I'd rather just warn the user, specify a default name for the tool, 
and hope they will install it so it's found on the PATH.  I'd like them 
to forget about re-running CMake.  1 problem to deal with instead of 2.  
It's more usable.  It's also more debuggable if the build file is 
unconditionally generated.  I can see what the Makefile dependency logic 
is and it won't change.

Another way of saying it, is I'm looking for something like a TRY_RUN 
capability for custom build rules.  Although specifically, I really only 
need a TRY_INSTALL.


Cheers,
Brandon Van Every