Explicitly specifying an executable (either with boost::filesystem::path
or boost::process::exe) and no arguments causes NULL to be passed as the
argument list.
Not only is this unexpected behaviour for the child process (which
doesn't even have argv[0]), it is not portable across UNIX systems. From
the execve(2) man page on Linux:
"On Linux, either argv or envp can be specified as NULL, which has the
same effect as specifying these arguments as a pointer to a list
containing a single NULL pointer. Do not take advantage of this
misfeature! It is nonstandard and nonportable: on most other UNIX
systems doing this will result in an error (EFAULT)."
