Fixes random crashes on Windows due to differences of STL types on the
binary level between different static libraries.
The differences are caused by the definition of _HAS_ITERATOR_DEBUGGING
and _SECURE_SCL in lib/precompiled.h.
All our engine static libs use precompiled headers but we didn't use
them for tinygettext because they aren't needed (except for these two
defines).
I've decided to add precompiled headers to tinygettext too instead of
just copying these defines. That should cause less headaches in the
future.
This was SVN commit r14983.
