Most of these are explained in Chapter 2 of the wolfSSL Manual (http://yassl.com/yaSSL/Docs-cyassl-manu … yassl.html). I have included brief explanations below as well.
This option was added for a specific customer build, which enabled a specific set of build options related to their environment.
This option is used when wolfSSL is being compiled for use with our SSL proxy.
Very small build using PSK, and eliminating many features from the library. Approximate build size for wolfSSL on an embedded system with this enabled is 21kB.
This turns on functions required over the standard build that will allow full functionality for building with the yaSSL Embedded Web Server.
Enabling this option will add extra compiler security checks.
Enabling fastmath will speed up public key operations like RSA, DH, and DSA. By default, wolfSSL embedded SSL uses the normal big integer math library. This is generally the most portable and generally easiest to get going with. The negatives to the normal big integer library are that it is slower and it uses a lot of dynamic memory. This option switches the big integer library to a faster one that uses assembly if possible. Assembly inclusion is dependent on compiler and processor combinations. Some combinations will need additional configure flags and some may not be possible. Help with optimizing fastmath with new assembly routines is available on a consulting basis.
Enabling fasthugemath includes support for the fastmath library and greatly increases the code size by unrolling loops for popular key sizes during public key operations. Try using the benchmark utility before and after using fasthugemath to see if the slight speedup is worth the increased code size.