No. C isn't an expressive enough language to write many solvers in. Many of the best solvers are basically impossible to write without meta-programming (where you write a generator for the n-stage version that is then able to generate the code for all the possible permuations), and there are also massive performance gains through symbolic-numeric approaches where the solver does introspection of the user function to rearrangements that aren't possible in a black-box framework.