2.3.12 source tarball build error

[Yasuaki Taniguchi/谷口康明]

Hello,

I started building Gnucash 2.3.12 from tarball, and found some errors.

(1) mysql-connector-c-noinstall-6.0.1-win32.zip is not on the mirror site.

(2) packaging/win32/libmysql.def is missing.

-- 
Yasuaki Taniguchi
  yasuakit at gmail.com