Most options in texmf.cnf of modern TeX distributions are ok for ConTeXt (in former times you had to care for ConTeXt's huge memory needs yourself and occasionally set some additional paths). The one thing left:
ConTeXt likes TeX's "write18" function enabled to run Metapost and some other tools in the background. That's a potential security risk (malicious TeX code could run any program with your user rights), so it's off (false) by default.
shell_escape = t