Fixed CORE-4127: Server crashes instead of reporting the error "key size exceeds implementation restriction".

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58213 65644016-39b1-43b1-bf79-96bc8fe82c15
Attempted to please the GCC compiler. If this doesn't help, another solution is to be backported from trunk.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58216 65644016-39b1-43b1-bf79-96bc8fe82c15
Fixed CORE-2912 - Exception when upper casing string with lowercase y trema (code 0xFF in ISO8859_1)

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/branches/B2_5_Release@58220 65644016-39b1-43b1-bf79-96bc8fe82c15