core: allow exclude (!) to work for regexp matches as well

only works when regexp are enabled, the only behavioural change is that
the check now happens sooner, setting a flag/ptr increment.

refs #3720
Issue #4392 - Compile-time errors in Icinga 1.9.2

   This commit fixes three compile-time errors that manifest
when using GCC version 2.95.3.  These are the result of intermixing
statements and declarations.

   This is a portability fix only.
Issue #4392 -- gcc errors in extinfo.c and ido2db.c

   Committing Changelog like I should have in the original commit.
Merge branch 'feature/exclude-with-regexp-3720' into next
Merge branch 'fix/compile-time_errors-4392' into next