perl plugin: #undef macros before poisoning them.

This fixes --enable-debug builds.
Fix for "conflicting types for 'ldap_init'"
Prefixed all the collectd specific functions and datatypes with the letter 'c'
Merge pull request #813 from njh/openldap_symbol_fix

Fix for "conflicting types for 'ldap_init'"
Fetch innodb stats from the information_schema when appropriate.

This supercedes #556, using the same query but assigning types.
I'd love some help deciding which types to use.
erroneous comparison, caught by clang
Merge pull request #824 from collectd/feature/update-innodb-stats

Fetch innodb stats from the information_schema when appropriate.
Merge pull request #396 from radford/perl-debug-compile-fix

perl plugin: #undef macros before poisoning them.
curl_json: allow escaping the separator