config.m4 currently defines developer-flags and coverage enable options. For static builds, these could conflict with other extensions. We should prefix them with "mongodb".

Since both of these options are intended for internal usage, BC should not be a concern and we can simply rename them.

That would leave only the following options without prefixes, both of which are already deprecated:

• PHP_ARG_WITH([openssl-dir])
• PHP_ARG_WITH([system-ciphers])