3.1.6 system() fails when at the ulimit of open files

[Chris Pearson]

With an open file limit of 1024:

mkdir z

yes|head -200|gawk '{print "hi" > ("z/"z++)}END{system("echo
hiho;date")}'   # the system() call works
yes|head -2000|gawk '{print "hi" > ("z/"z++)}END{system("echo
hiho;date")}'   # the system() call doesnt work, even though all 2000
files are created.

So, I guess whatever decides to make room to open a new file getting
called for system(), which is inconsistant with how open file juggling
is handled by gawk in other cases, and probably easily fixed.   Or at
the very least should print an error if not.