build
=====
After a FLASH simulation has been setup - ie the simulation-dependent source files 
have been assembled - this must be compiled into an executable.  This is done with 
the ``flmake build`` command.  Under the covers, the build command simply subprocesses 
the ``make`` utility, which uses the ``Makefile`` constructed during setup. 

**USAGE**:: 

    flmake build [options]

All options specified on the command line are transparently passed down to make.  Note
that the build stage takes place in a separate build directory which is different from 
the setup directory.  This makes it possible to rebuild with out having to re-setup
the simulation.