Use symbolic constants.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59427 65644016-39b1-43b1-bf79-96bc8fe82c15
Simplify QUADCONST definition for Windows.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59428 65644016-39b1-43b1-bf79-96bc8fe82c15
I hope I fixed the issues noted by Adriano about my generators commit.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59429 65644016-39b1-43b1-bf79-96bc8fe82c15