@swankster
Solution was, finding this gem https://github.com/kivy/kivy/wiki/Creating-a-64-bit-development-environment-with-MinGW-on-Windows then making a few modifications. Basically rebuilding MySQL Connector.C 6.1\lib\libmysql.dll with gendef.exe
will need to Install Ruby x64, I used (rubyinstaller-2.2.2-x64.exe)
set Ruby...\bin to System Variables.
copy C:\Program Files\MySQL\MySQL Connector.C 6.1 to C: and rename as \mysql-connector
open cmd window
C:\mysql-connector\lib
> gendef.exe libmysql.dll
> dlltool -v --dllname libmysql.dll --def libmysql.def --output-lib libmysql.lib
> gem install mysql2 --no-rdoc --no-ri -- '--with-mysql-lib="C:\mysql-connector\lib" --with-mysql-include="C:\mysql-connector\include"'
copy c:\mysql-connector\lib\libmysql.lib
to c:\Program Files\MySQL\MySQL Server 5.6\lib
copy c:\Ruby22-x64\lib\ruby\gems\2.2.0\gems\mysql2-0.3.18-x64-mingw32\vendor\libmysql.dll
to c:\Program Files\MySQL\MySQL Server 5.6\lib
Now build MySql Driver for QT. I used third party QT 64 from http://www.tver-soft.org/qt64
put in System Variables
C:\Qt\5.4.1-x64\mingw492r1-sjlj-rev1\qt-5.4.1-x64-mingw492r1-sjlj-rev1\bin;
C:\Qt\5.4.1-x64\mingw492r1-sjlj-rev1\mingw64\bin;
C:\Qt\5.4.1-x64\mingw492r1-sjlj-rev1\mingw64\lib
Create QT cmd window (needs custom qtenv.bat file, copied from other QT version and modified for x64)
from QT cmd x64
set mysql=C:\PROGRA~1\MySQL\MYSQLS~1.6 (must be short names)
cd c:\Qt\qt-5.4.1-src\qtbase\src\plugins\sqldrivers\mysql
qmake "INCLUDEPATH+=%mysql%\include" "LIBS+=%mysql%\lib\libmysql.lib" -o Makefile mysql.pro
mingw32-make
copy qsqlmysql.dll and qsqlmysqld.dll from C:\Qt\qt-5.4.1-src\qtbase\plugins\sqldrivers to c:\Qt\5.4.1-x64\mingw492r1-sjlj-rev1\qt-5.4.1-x64-mingw492r1-sjlj-rev1\plugins\sqldrivers
copy %mysql%\lib\libmysql.dll c:\windows
Hope this helps someone else save a few days worth of time and aggravation.
