I got following error while installing Apache from ports

# cd /usr/ports/www/apache21
# make

To enable a module category: WITH__MODULES
To disable a module category: WITHOUT__MODULES

Per default categories are:
AUTH AUTHN AUTHZ DAV MISC
Categories available:
AUTH AUTHN AUTHZ DAV EXPERIMENTAL LDAP MISC PROXY SSL SUEXEC THREADS

To see all available knobs, type make show-options
To see all modules in different categories, type make show-categories
You can check your modules configuration by using make show-modules

Dependency warning: used OpenSSL version contains known vulnerabilities
Please update or define either WITH_OPENSSL_BASE or WITH_OPENSSL_PORT
*** Error code 1

Stop in /usr/ports/www/apache21.

I tryed upgrading ports with cvsup, but it won’t help.

Solved it by adding

WITH_OPENSSL_BASE=YES

to

/etc/make.conf