databases/mysql80-{client, server}: Update ports to latest version 8.0.13
This update fixes several issues including CVEs.
Bug-fixes:

• Return better error messages for OpenSSL errors
• Incorrect copying of an integer value by X Plugin caused an

	    error relating to misaligned memory access

Improvement:

• Important Change: X Protocol now provides a connection pooling option

Upstream notes: https://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-13

While here, fix the build with GCC-based architectures too (ported from fix on MySQL57)

Sponsored by: The FreeBSD Foundation