Prior to this commit, we only allowed CMake options to be specified according to
a finite set of values. For example if an option "WOLFSSL_FEATURE" was permitted
to take only the values "yes" and "no" and a user ran
`cmake -DWOLFSSL_FEATURE=ON`, that would fail because ON isn't in `[yes, no]`.
However, this behavior runs counter to CMake's way of evaluating boolean values,
which permits a variety of values that evaluate to true/false (see
https://cmake.org/cmake/help/latest/command/if.html#basic-expressions). This
commit will allow the user to specify any value for a build option. If it's not
in the predefined set of values, we use CMake's "if" logic to reduce the value
to yes or no.
9634a54b8f