The plugincheck_procs doens't return perfdata.
This patch will enable perf data.
Please put it into the next release.
I agree with the intention of this patch, I find myself constantly patching the source of check_procs.c whenever I add a new nagios installation, although my patch consisted only of a single line (printf (" | procs=%d",procs);) without any of the other parameters.
In the next release, the check_procs plugin will provide performance data.