Disable and disallow static linking

Disable and disallow static linking

Linking BIND 9 programs and libraries statically disables several
important features:

  * dlopen() - relied on by dynamic loading of modules, dlz, and dyndb,

  * RELRO (read-only relocations) and ASLR (address space layout
    randomization) - security features which are important for any
    program interacting with the network and/or user input.

Disable and disallow linking BIND 9 binaries statically, thus enforcing
dlopen() support and allowing use of RELRO and ASLR by default.