cmake: new add_option_defs helper, add KEYLOG_EXPORT build param

[redbaron]

Description

Add add_option_defs helper which cover simple case of setting compile definitions when build option is selected. New helper uses named arguments and adds following QoL improvements:

• optionally infer default values from list of possible values. First possible value becomes default.
• optionally append default value to helper string. Helper string and default values can't go out of sync
• support adding defines if build option is set. It covers many simple cases like new WOLFSSL_KEYLOG_EXPORT

Fixes #8165

Testing

1. Build before and after patch, diffed CMakeCache.txt files to find only new WOLFSSL_KEYLOG_EXPORT function is different.

Checklist

• [ ] added tests
• [ ] updated/added doxygen
• [ ] updated appropriate READMEs
• [ ] Updated manual and documentation

[wolfSSL-Bot]

Can one of the admins verify this patch?

[embhorn]

Hi @redbaron

Thanks for opening this PR. We require contributors to be approved by the wolfSSL team. Could you please send an email to support@wolfssl.com to request an application form?

Thanks, @embhorn - wolfSSL Support

[embhorn]

@redbaron is approved as a wolfSSL contributor